AmpleJon | Ample Air

Toshiba air conditioner fault codes

by AmpleJon | Aug 3, 2026

When your Toshiba system stops and shows a code, that code is the system telling you roughly where the problem is. Roughly is the key word. A fault code points in a direction, it rarely names the exact fix. Find your system below, tap your code, and it will take you straight to what it means and what to do.

Before you try anything: the only DIY steps that are ever safe are switching the system off at the isolator (and waiting 20 to 30 minutes), cleaning or checking filters, checking the controller settings and batteries, and keeping the outdoor unit clear. Anything behind a panel, anything electrical, and anything involving refrigerant or gas is licensed work. If a code below says switch off and call, please take it at its word.

How to read the tables: 🟢 means there is a safe first step worth trying. 🟡 means book a service, the system needs a technician. 🔴 means switch the system off at the isolator and call us on (02) 4760 0100.

RAV light commercial (Digital Inverter / Super Digital Inverter) — code set applies across RAV indoor types: ducted, cassette, under-ceiling and high-wall (source section is the high-wall troubleshooting chapter of SVM-12042)

Where the code shows: Check code shows on the wired remote controller display. On wireless-receiver models the fault is signalled by the indoor unit's Ready / Timer / Operation lamps flashing in block patterns (alternate or simultaneous flashing depending on the fault family); per-code lamp patterns were not legible in extraction..

Tap your code: E01 E02 E03 E04 E08 E09 E10 E18 F01 F02 F04 F06 F07 F08 F10 F12 F13 F15 F29 F31 H01 H02 H03 H04 L03 L07 L08 L09 L10 L20 L29 L30 P01 P03 P04 P05 P07 P10 P12 P15 P19 P20 P22 P26 P29 P31

Code	What it means	What to do
E01	The controller can't hear the indoor unit, the two have stopped talking to each other. Remote controller receiving error, detected on the controller side. Usually controller wiring; system stops (a second controller, if fitted, keeps running).	🟢 Switch the system off at the isolator, wait 20-30 minutes, then switch it back on. If the code returns, book a service.
E02	The controller can't get its commands through to the indoor unit. Remote controller transmission (send) error, controller sending circuit or wiring.	🟢 Power-cycle at the isolator and wait 20-30 minutes before switching back on. If it comes back, book a service.
E03	The indoor unit has stopped hearing from its controller. Communication stop between indoor unit and remote controller / network adaptor, detected on the indoor side. Classic appearance after a power interruption.	🟢 Turn the system off at the isolator, wait 20-30 minutes, then turn it back on. If the code returns, book a service.
E04	The indoor and outdoor units have lost contact with each other. Indoor-outdoor serial communication stop, inter-unit wiring or a board-level signal fault. Often shows after a blackout or brown-out.	🟢 Switch off at the isolator, wait 20 to 30 minutes, switch back on. If the code returns, book a service, the connection between the units needs a technician to check it.
E08	Two indoor units have been given the same address, so the system can't tell them apart. Duplicated indoor unit address, an installer addressing/commissioning issue on grouped systems.	🟡 This is a setup fault, not something you can fix at the controller, book a service.
E09	More than one controller is set as the main controller. Duplicated master remote controllers in a two-controller installation. The master unit stops; the follower keeps running.	🟡 Book a service so the controllers can be reconfigured, one main, the rest subs.
E10	A communication fault inside the indoor unit's own circuit board. Communication error between CPUs on the indoor PCB.	🟡 Book a service, this points at the indoor unit's electronics.
E18	Indoor units in the same group have stopped talking to each other. Communication stop between master and follower indoor units (twin/group setups), wiring, or one unit lost power.	🟢 Power-cycle the whole system at the isolator (all indoor units), wait 20-30 minutes and restore power. If the code returns, book a service.
F01	A temperature sensor on the indoor coil isn't reading properly. Indoor heat exchanger sensor (TCJ, liquid side) open or short circuit.	🟡 No safe DIY fix for a sensor fault, book a service.
F02	The indoor coil's main temperature sensor has failed. Indoor heat exchanger sensor (TC, vapour side) out of place, open or short circuit.	🟡 Book a service, the sensor or its connection needs replacing.
F04	The sensor watching the compressor's outlet temperature has failed. Discharge temperature sensor (TD) open or short circuit, outdoor unit.	🟡 Book a service. The unit is protecting itself from running blind on a critical sensor.
F06	An outdoor coil temperature sensor isn't reading properly. Outdoor heat exchanger sensor (TE) open or short circuit.	🟡 Book a service, sensor faults aren't homeowner-fixable.
F07	The outdoor unit's liquid-line temperature sensor has failed. Liquid temperature sensor (TL) open or short circuit.	🟡 Book a service.
F08	The outdoor air temperature sensor has failed. Ambient temperature sensor (TO) open or short circuit. The doc notes the system keeps running with this fault.	🟡 The system may keep running, but book a service to have the sensor replaced.
F10	The indoor return-air (room) temperature sensor has failed. Room temperature sensor (TA) open or short circuit.	🟡 Book a service, the unit can't read the room temperature properly until the sensor is replaced.
F12	The outdoor unit's suction temperature sensor has failed. Suction temperature sensor (TS) open or short circuit.	🟡 Book a service.
F13	The temperature sensor on the inverter's heat sink has failed. Heat sink sensor (TH) fault on the outdoor power electronics.	🟡 Book a service, this is inside the outdoor unit's electronics.
F15	Two outdoor temperature sensors appear to be swapped or fitted in the wrong positions. Sensor miswiring / mis-mounting (TE and TS) detected by the outdoor unit.	🟡 Book a service, a technician needs to refit the sensors correctly.
F29	The indoor unit's memory chip has a fault. Indoor EEPROM error, settings memory on the indoor PCB.	🟡 Book a service, the indoor board needs attention.
F31	The outdoor unit's memory chip has a fault. Outdoor PCB EEPROM error.	🟡 Book a service, the outdoor board needs attention.
H01	The compressor shut down under load, a serious outdoor unit fault. Compressor breakdown: operating frequency drops after start-up, then the unit stops. Can point to supply voltage problems or an overloaded refrigeration circuit.	🔴 Switch the system off at the isolator and call us, running it risks further compressor damage.
H02	The compressor is jammed and can't start. Compressor lock, over-current detected at compressor start-up; can also indicate a wiring (open phase) fault.	🔴 Switch off at the isolator and call us. This one needs a technician before the unit runs again.
H03	The outdoor unit can't measure its own electrical current properly. Current detection circuit error on the outdoor PCB.	🟡 Book a service, this is an outdoor circuit-board fault.
H04	The compressor's overheat protection has tripped. Case thermostat operation, abnormal compressor overheat. Service checks include refrigerant loss, service valves not fully open, and the expansion valve.	🔴 Switch the system off at the isolator and call us, it can indicate refrigerant loss.
L03	Two indoor units both think they're the group leader. Duplicated indoor group master unit, addressing/commissioning issue.	🟡 Book a service, grouping needs to be re-commissioned.
L07	A stand-alone indoor unit has group wiring connected to it. Group cable connected to an individual (non-grouped) indoor unit. The system re-enters address setup automatically if grouping is wrong at power-on.	🟡 Book a service, this is an installation setup issue that needs a technician.
L08	The indoor units haven't been given their group addresses yet. Indoor group address unset, commissioning incomplete.	🟡 Book a service so the addressing can be completed.
L09	The indoor unit doesn't know its own capacity setting. Indoor capacity unset, a commissioning DIP-switch/setting on the indoor board.	🟡 Book a service, a technician sets this on the indoor unit's board.
L10	The outdoor unit's replacement circuit board hasn't been set up for this model. Unset jumper / model type on the outdoor service PCB.	🟡 Book a service, the outdoor board needs its model setting completed.
L20	Two units on the central control network share the same address. Duplicated central control system address (TCC-LINK / network adaptor setting).	🟡 Book a service, the central-control addressing needs correcting.
L29	Circuit boards inside the outdoor unit have stopped talking to each other. Communication error between outdoor MCUs (main board and inverter boards).	🟡 Book a service, this is internal to the outdoor unit's electronics.
L30	An external safety device wired to the unit has told it to stop. Outside interlock input, abnormal stop signalled by external equipment connected to the indoor unit.	🟡 Book a service. If you know an external system (e.g. building safety interlock) is connected, mention it when you call.
P01	The indoor fan motor has a fault. Indoor AC fan error.	🟡 Book a service, fan motor faults need a technician.
P03	The compressor is running too hot at its outlet. Discharge temperature (TD) exceeded its limit. Service checks include refrigerant loss and the electronic expansion valve.	🔴 Switch the system off at the isolator and call us, this can indicate refrigerant loss.
P04	Pressure inside the system climbed too high and it shut itself down for protection. High-pressure system error, refrigeration circuit overload, coil sensor or high-pressure switch.	🔴 Switch off at the isolator and call us. It's fine to check that filters are clean and the outdoor unit isn't blocked by leaves or objects, but don't keep running it if the code returns.
P05	The power coming into the unit isn't right. Power supply error, supply voltage out of range or a phase problem.	🟡 If the whole property just had a power event, try one power-cycle at the isolator (wait 20-30 minutes). If the code returns, book a service.
P07	The outdoor unit's power electronics got too hot. Heat sink overheat, inverter heat sink exceeded its temperature limit; service checks include heat-sink mounting and airflow path.	🟡 Make sure the outdoor unit has clear space around it and isn't blocked, then book a service if the code returns.
P10	The indoor unit found water where it shouldn't be, the condensate isn't draining away. Overflow detected, float switch tripped in the drain pan.	🟡 Book a service promptly, a blocked drain can leak into the ceiling or wall if the unit keeps running.
P12	The indoor fan motor has a fault. Indoor DC fan error, over-current, locked rotor or position-detection fault.	🟡 Book a service, the fan motor or its drive board needs a technician.
P15	The system thinks it has lost refrigerant. Gas leak detection, discharge (TD) or suction (TS) temperatures above their limits. Service checks include leak testing, service valves and the expansion valve.	🔴 Switch the unit off at the isolator and call us, don't keep running a system that may be low on refrigerant.
P19	The valve that switches the system between heating and cooling isn't working properly. 4-way (reversing) valve system error, detected when the indoor coil temperature moves the wrong way after heating starts.	🟡 Book a service, the reversing valve needs a technician.
P20	The system shut itself down to protect against high pressure. High-pressure protective operation, causes include blocked airflow over the coils, dirty heat exchangers, closed service valves or refrigerant overcharge.	🔴 Switch off at the isolator and call us. Checking that filters are clean and the outdoor unit is clear of obstructions is safe; repeated running against this fault isn't.
P22	The outdoor fan system has a fault. Outdoor fan error, fan motor lock, supply voltage or fan drive board.	🟡 Check nothing is jammed against the outdoor unit, then book a service.
P26	A short-circuit was detected in the compressor's drive electronics. Inverter Idc protection, short-circuit fault in the compressor driving element or compressor windings.	🔴 Switch the system off at the isolator and call us, this is an electrical fault that needs a technician.
P29	The outdoor unit can't sense the compressor motor's position. Position detection circuit error on the compressor drive.	🟡 Book a service, this sits in the outdoor unit's drive electronics.
P31	This unit stopped because another indoor unit in its group has a fault. Follower unit stopped by a warning from the group master (master shows E03, L03, L07 or L08). This unit itself is usually fine.	🟡 Check the other indoor units' controllers for a different code and book a service quoting that code too.

TCC-LINK central control (used with RAV / VRF systems) — codes shown on the central controller, not the room controller

Where the code shows: Central controller display. The manual notes the same underlying fault can show different codes depending on which device detects it..

Tap your code: C05 C06 C12 P30

Code	What it means	What to do
C05	The central controller can't send commands onto the control network. Central control system communication (send) error, can also indicate duplicated central control devices on the network. Units keep running under their own controllers.	🟡 Individual units should still work from their own controllers, book a service for the central control system.
C06	The central controller can't receive replies from the control network. Central control system communication (receive) error, network wiring (U3/U4 terminals), adaptor board or termination resistance.	🟡 Book a service, the central-control connection needs a technician to check it.
C12	A device wired into the general-purpose control interface has reported a fault. Batched warning from equipment connected via the TCC-LINK/general-purpose device control interface.	🟡 Book a service and mention any third-party equipment connected to the air conditioning controls.
P30	One of the units in a controlled group has its own fault. Group follower unit defective, reported at the central controller; the affected unit's own controller shows the specific code. The same code can also indicate duplicated central control addresses (shown with L20).	🟡 Check each unit's own controller for its code and book a service quoting what you find.

RAS residential hi-wall inverter splits (service manual SVM-10050-1)

Where the code shows: No code shows in normal use. When a fault is logged, all lamps on the indoor unit flash together about 5 times a second and the unit beeps for 10 seconds. A technician reads a two-character check code (range 00-33, letters shown as 7-segment characters) through the remote controller's hidden service mode (CHECK button); '7F' on the display just means the fault memory was cleared, not a fault..

Tap your code: 04 07 08 0C 0d 11 12 14 16 17 18 19 1A 1b 1C 1d 1E 1F

Code	What it means	What to do
04	The indoor and outdoor units have stopped talking to each other. Serial signal error between indoor and outdoor units, connecting cable, inter-unit wiring or a signal circuit on either board. The outdoor unit won't start while this is active.	🟢 Switch the system off at the isolator, wait 20-30 minutes, then switch it back on. If the fault indication returns, book a service.
07	The outdoor unit went quiet mid-run, often the compressor protecting itself or low refrigerant. Return serial signal stopped during operation. Causes listed: compressor thermal cut-out, gas shortage/leak, or a momentary power failure.	🔴 If this appeared straight after a power interruption, one power-cycle at the isolator (with a 20-30 minute wait) is fine to try. Otherwise switch the unit off and call us, it can mean low refrigerant.
08	The valve that switches the system between heating and cooling is working in reverse. 4-way (reversing) valve inverse error: the indoor coil temperature (TC) moves the wrong way after heating starts. The unit keeps operating.	🟡 Book a service, the reversing valve needs a technician.
0C	The room temperature sensor has failed. TA sensor short-circuit or disconnection. The unit keeps operating.	🟡 The unit may keep running but can't read the room properly, book a service.
0d	The indoor coil's temperature sensor has failed. TC (indoor heat exchanger) sensor out of place, disconnected or short-circuited. The unit keeps operating.	🟡 Book a service, the sensor needs refitting or replacing.
11	The indoor fan motor has a fault. Fan motor failure, locked rotor, short-circuit or disconnection, or its drive circuit on the indoor board.	🟡 Book a service, fan motor faults need a technician.
12	A fault on the indoor unit's circuit board. Other indoor PCB trouble, board replacement is the listed remedy.	🟡 Book a service.
14	The inverter tripped on a sudden current spike. Inverter over-current protective circuit operated (short-time). Outdoor unit stops.	🟡 Book a service, repeated trips point at the outdoor electronics or compressor.
16	The compressor drive can't sense the motor, possibly a short inside the compressor. Position-detect circuit error or short-circuit between compressor windings. Remedy path: PCB or compressor replacement.	🔴 Switch the unit off at the isolator and call us, don't keep restarting it.
17	The outdoor unit can't measure its own electrical current properly. Current-detect circuit error on the outdoor board.	🟡 Book a service, this is an outdoor circuit-board fault.
18	An outdoor temperature sensor isn't reading properly. Outdoor heat exchanger sensor (TE) or suction sensor (TS) out of place, disconnected or short-circuited.	🟡 Book a service.
19	The sensor watching the compressor's outlet temperature has failed. Discharge temperature sensor (TD) disconnected or short-circuited.	🟡 Book a service.
1A	The outdoor fan system has a fault. Outdoor fan drive error, position-detect fault, over-current protection or fan lock.	🟡 Check nothing is jammed against the outdoor unit, then book a service.
1b	The outdoor air temperature sensor has failed. Outdoor ambient sensor (TO) error. The unit keeps running, and the doc notes this fault isn't shown on the indoor lamps.	🟡 The system keeps working but may behave oddly in extreme weather, book a service.
1C	The compressor isn't responding to its drive electronics. Compressor drive output error, compressor lock or a missing phase in its wiring.	🔴 Switch the unit off at the isolator and call us.
1d	The compressor won't turn. Compressor does not rotate, current protection doesn't engage in the expected window after start-up.	🔴 Switch the unit off at the isolator and call us, repeated start attempts can make it worse.
1E	The compressor ran dangerously hot. Discharge temperature exceeded 117 degC. Service checks include the TD sensor, refrigerant leakage and the expansion valve.	🔴 Switch the system off at the isolator and call us, this can indicate refrigerant loss.
1F	The compressor has failed, a major outdoor unit fault. Compressor breakdown. Service checks include supply voltage (220-240 V +/-10%) and refrigeration-cycle overload, including a short-circuited outdoor airflow path.	🔴 Switch the unit off at the isolator and call us.

Code still showing after a reset? Mention the code and your system type when you book and our office can line up the right technician and likely parts before we arrive.

Book a service or call (02) 4760 0100 (24-hour line, Penrith & Blue Mountains).

Codes vary between models and generations, and manufacturers revise them. This guide is compiled from official service documentation and checked by Ample Air, but it is general information, not a diagnosis. Refrigerant and electrical work must be carried out by licensed technicians. Ample Air, ARC licences AU12976 & AU15788. Last verified August 2026.

Mitsubishi Electric fault codes & blink patterns

by AmpleJon | Aug 3, 2026

When your Mitsubishi Electric system stops and shows a code, that code is the system telling you roughly where the problem is. Roughly is the key word. A fault code points in a direction, it rarely names the exact fix. Find your system below, tap your code, and it will take you straight to what it means and what to do.

Mr Slim P Series (A-control) — inverter-era ducted, cassette, ceiling-suspended and wall-mounted light commercial

Where the code shows: Two-character code on the wired wall controller (PAR series). Many codes also flash on service LEDs (LED1 green / LED2 red — flash counts noted per code; the source doc does not say which board carries these LEDs) and map to a 4-digit M-NET code when on a central controller..

Tap your code: EA Eb EC E0 E1 E2 E3 E4 E5 E6 E7 E8 E9 ED EF P1 P2 P4 P5 P6 P8 P9 F1 F2 F3 F4 F5 F7 F8 F9 FA U1 U2 U3 U4 U5 U6 U7 UA Ud UE UF UH UL

Code	What it means	What to do
EA	The indoor and outdoor units are wired to each other incorrectly, or more indoor units are connected than the outdoor unit allows. Checked at the outdoor unit. M-NET equivalent 6844.	🟡 Book a service and quote the code, this is a wiring or setup issue that needs a technician.
Eb	The wiring between the indoor and outdoor unit is crossed or disconnected. Checked at the outdoor unit. Wrong cable size/spec is a known cause. M-NET equivalent 6845.	🟡 Book a service and quote the code, this is a wiring or setup issue that needs a technician.
EC	The units could not finish their start-up handshake in time. Start-up time over; electrical interference or wrong cable spec are cited causes. M-NET equivalent 6846.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E0	The wall controller is not receiving a signal from the unit. Remote controller transmission error (receiving side). LED1 2 flashes / LED2 3 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E1	A fault with the wall controller itself or how it has been grouped. On grouped or twinned systems, controller addressing and master-wiring are the usual suspects.	🟡 Book a service and quote the code.
E2	A fault with the wall controller or its addressing. Same checks as E1, grouping/addressing, and on twinned systems the controller must be wired to the master indoor unit.	🟡 Book a service and quote the code.
E3	The wall controller cannot transmit its signal to the unit. Remote controller transmission error (transmitting side). LED1 2 flashes / LED2 3 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E4	The indoor unit is not receiving the wall controller's signal. LED1 2 flashes / LED2 3 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E5	The indoor unit cannot transmit its reply to the wall controller. LED1 2 flashes / LED2 3 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E6	The indoor and outdoor units have lost communication with each other. Classic after power is restored in the wrong order (outdoor before indoor); interference on the S1/S2 line (e.g. from a drain pump wired into it) is another cause. M-NET equivalent 6840. LED1 2 flashes / LED2 2 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E7	Communication fault between the indoor and outdoor units (detected at the indoor unit, transmitting side). Service checks include 12/24 V DC on S2–S3 and any condensate pump wired at the indoor unit. LED1 2 flashes / LED2 2 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E8	The outdoor unit is not receiving the indoor unit's signal (S2/S3 line). Powering up in the wrong order is a common cause, indoor should come on before outdoor. M-NET equivalent 6840.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
E9	The outdoor unit cannot transmit to the indoor unit (S2/S3 line). M-NET equivalent 6841.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
ED	Circuit boards inside the outdoor unit have lost serial communication with each other. Can be caused by an M-NET interface board that is not seated correctly. M-NET equivalent 403. LED1 2 flashes / LED2 5 flashes.	🟡 Book a service and quote the code.
EF	A non-specific communication error, usually caused by electrical interference. Also logged as an M-NET transmission error. Manufacturer guidance is a 30-second power-down of the outdoor unit. M-NET equivalent 6607. LED1 2 flashes / LED2 4 flashes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
P1	The return-air temperature sensor is not reading properly or has come unplugged. TH1 thermistor open/short circuit. LED1 4 flashes / LED2 1 flash.	🟡 Book a service and quote the code.
P2	The indoor pipe (liquid line) temperature sensor is not reading properly or has come unplugged. TH2 thermistor open/short circuit. LED1 4 flashes / LED2 1 flash.	🟡 Book a service and quote the code.
P4	The condensate drain sensor is faulty or disconnected. DS open/short circuit. LED1 4 flashes / LED2 2 flashes.	🟡 Book a service and quote the code.
P5	Condensate water is not draining away, the level in the tray is high, pointing to a failed drain pump or a blocked drain. LED1 4 flashes / LED2 2 flashes.	🟡 Switch the unit off if you can see any water dripping, and book a service.
P6	The indoor coil froze up in cooling or overheated in heating, almost always an airflow problem. Frost/overheat protection. Dirty filters, a blocked return-air path or a fan fault are the usual causes. LED1 4 flashes / LED2 3 flashes.	🟢 Clean or check the return-air filters and make sure vents are open, then power-cycle at the isolator with a 20–30 minute wait. If the code returns, book a service.
P8	Pipe temperatures are not changing the way they should, often a sign the system has lost refrigerant. Abnormal pipe temperature; can also be a temperature sensor mounted out of position. LED1 4 flashes / LED2 4 flashes.	🔴 Switch the system off at the isolator and call for service.
P9	The coil (condenser/evaporator) temperature sensor is faulty or has come off the board. TH5 thermistor open/short circuit. LED1 4 flashes / LED2 1 flash.	🟡 Book a service and quote the code.
F1	The three-phase power supply is connected in the wrong phase order. Reverse phase detection. M-NET equivalent 4103. LED1 1 flash / LED2 1 flash.	🟡 Book a service and quote the code, this points to a power-supply problem.
F2	One phase (L3) of the three-phase power supply is missing. Open-phase detection; protection devices in the supply may have opened. M-NET equivalent 4102. LED1 1 flash / LED2 1 flash.	🟡 Book a service and quote the code, this points to a power-supply problem.
F3	The low-pressure switch circuit is open, a disconnected plug or failed contact. 63L connector. Mapped to M-NET 5202 in the source. LED1 1 flash / LED2 2 flashes.	🟡 Book a service and quote the code.
F4	The compressor's internal overheat thermostat circuit is open. 49C connector open or contact failure. Mapped to M-NET 4124. LED1 1 flash / LED2 2 flashes.	🟡 Book a service and quote the code.
F5	The high-pressure switch circuit is open, a disconnected plug or failed contact. 63H switch. Mapped to M-NET 5201 in the source. LED1 1 flash / LED2 2 flashes.	🟡 Book a service and quote the code.
F7	The phase-detection circuit on the outdoor board has failed. Usually a faulty outdoor PCB. M-NET equivalent 4118. LED1 1 flash / LED2 3 flashes.	🟡 Book a service and quote the code.
F8	The outdoor board's input circuit is faulty. Points to a defective outdoor board. LED1 1 flash / LED2 3 flashes.	🟡 Book a service and quote the code.
F9	Two or more protection-device circuits are open at the same time. M-NET equivalent 4119. LED1 1 flash / LED2 2 flashes.	🟡 Book a service and quote the code.
FA	Either the L2 supply phase is missing or the compressor overcurrent relay circuit is open. 51CM connector / thermal relay. M-NET equivalent 4108. LED1 1 flash / LED2 2 flashes.	🟡 Book a service and quote the code.
U1	The system shut down because refrigerant pressure went too high. 63H high-pressure switch tripped (M-NET 1302; LED1 3 flashes / LED2 2 flashes). Blocked outdoor coil, outdoor fan failure, a system blockage or dirty indoor filters in heating are the listed causes. The blog source also lists U1 as 'direct cut operation' on some models.	🟡 Check the filters are clean and the outdoor unit has clear space around it, then power-cycle at the isolator with a 20–30 minute wait. If it trips again, book a service.
U2	The compressor ran too hot, often because the system is low on refrigerant. High discharge temperature (M-NET 1102; LED1 3 flashes / LED2 1 flash). Can also be the compressor's internal thermostat (49C) tripping, a faulty thermistor, or very high ambient conditions.	🔴 Switch the system off at the isolator and call for service.
U3	The discharge temperature sensor is open or short circuit. Mapped to M-NET 5104 in the source. LED1 3 flashes / LED2 5 flashes.	🟡 Book a service and quote the code.
U4	The outdoor temperature sensor is open or short circuit. Mapped to M-NET 5105 in the source. LED1 3 flashes / LED2 5 flashes.	🟡 Book a service and quote the code.
U5	The inverter's heat sink is running too hot. TH8 heat-sink sensor (M-NET 4230; LED1 3 flashes / LED2 6 flashes). Poor airflow around the heat sink, missing silicone paste or a faulty thermistor are cited causes.	🟡 Book a service and quote the code.
U6	The compressor is drawing too much electrical current. Compressor overcurrent / overload cut-off (M-NET 4250; LED1 3 flashes / LED2 4 flashes). Needs inverter output tests and electrical checks.	🔴 Switch the system off at the isolator and call for service.
U7	Discharge superheat is too low, the refrigerant metering is not right. Points to the TH4 sensor reading or LEV (expansion valve) operation. M-NET equivalent 1520. LED1 3 flashes / LED2 1 flash.	🟡 Book a service and quote the code.
UA	Compressor overcurrent, the terminal relay has operated. Not in the 2011 compendium, but confirmed in independent A-control lists: compressor over current (terminal relay operation).	🔴 Switch the system off at the isolator and call for service.
Ud	The unit stopped on overheat protection. Source gives no further cause. Confirmed as 'over heat protection' in ARMA and official Mitsubishi lists.	🟡 Book a service and quote the code.
UE	High refrigerant pressure caused by a closed service (ball) valve. Typically seen at commissioning when a stop valve was left shut. Confirmed as 'high pressure error (ball valve closed)' in ARMA and official Mitsubishi lists.	🔴 Switch the system off at the isolator and call for service.
UF	The compressor is locked and cutting out on overcurrent, at start-up or while running. Shown for both start-up locked and operating locked in the A-control list; the official Mitsubishi list gives 'compressor overcurrent interruption (when compressor locked)'.	🔴 Switch the system off at the isolator and call for service.
UH	The current sensor is giving faulty readings. Confirmed as 'current sensor error' in ARMA and official Mitsubishi lists.	🟡 Book a service and quote the code.
UL	Refrigerant pressure is abnormally low, a possible leak. Confirmed as 'abnormal low pressure' in independent A-control lists; a possible refrigerant leak.	🔴 Switch the system off at the isolator and call for service.

Mr Slim P Series (K-control) — older R22-era ducted and cassette light commercial

Where the code shows: Code shown on the K-control wired remote controller..

Tap your code: E0 P1 P2 P3 P4 P5 P6 P7 P8

Code	What it means	What to do
E0	The wall controller and indoor unit are not communicating. Transmit/receive signal error. Can also be wrong group or master/slave settings (CN40, SW2, SW6).	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
P1	The intake (return-air) temperature sensor is faulty. TH1 thermistor, roughly 6.4 kilohm at 20°C when healthy.	🟡 Book a service and quote the code.
P2	The pipe/coil temperature sensor is faulty. TH2 thermistor, roughly 6.4 kilohm at 20°C when healthy.	🟡 Book a service and quote the code.
P3	Signal transmission error within the system. Same checks as E0, communication between indoor unit and controller, or group/master-slave settings (CN40, SW2, SW6).	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the code comes back, book a service.
P4	The condensate drain sensor is faulty. Sensor resistance, connection and continuity checks.	🟡 Book a service and quote the code.
P5	The drain overflow protection has tripped, condensate is not getting away. Blocked drain or tray, drain pump failure, or a faulty sensor.	🟡 Switch the unit off if you can see any water dripping, and book a service.
P6	The indoor coil's frost or overheat protection tripped, usually an airflow problem. Detected by the indoor coil sensor; lack of airflow or a refrigerant charge problem are the listed causes.	🟢 Clean or check the return-air filters and make sure vents are open, then power-cycle at the isolator with a 20–30 minute wait. If the code returns, book a service.
P7	System address setting error. CN40, SW2 and SW6 settings; possible board fault.	🟡 Book a service and quote the code.
P8	The outdoor unit has a fault, indoor temperatures are not changing after start-up. No indoor temperature change after about 9 minutes of running. Listed causes: outdoor unit tripped, refrigerant charge problem, lack of airflow, or TH2 faulty/badly mounted.	🔴 Switch the system off at the isolator and call for service.

Mr Slim K-control — PUH-EK outdoor units (LED diagnostics)

Where the code shows: LEDs LD1–LD8 on the outdoor unit control board: steady ON means a normal operating status, flashing means the fault listed here..

Tap your code: LD1 (flashing)LD2 (flashing)LD3 (flashing)LD4 (flashing)LD5 (flashing)LD6 (flashing)LD7 (flashing)LD8 (flashing)

Code	What it means	What to do
LD1 (flashing)	Three-phase power is connected in the wrong phase order. Reverse-phase detect. Steady LD1 just means the compressor is being called (normal).	🟡 Book a service and quote the code, this points to a power-supply problem.
LD2 (flashing)	A supply phase is missing, or a protection component's circuit is open. Open-phase detect. The compendium also lists CH, 52C, 21S4, SV, 63H and 26C open circuits under LD2. Steady LD2 = heating call (normal).	🟡 Book a service and quote the code.
LD3 (flashing)	The outdoor coil/pipe sensor is open or short circuit. May be disconnected, or an outdoor board fault. Steady LD3 = 63H1 operating (normal).	🟡 Book a service and quote the code.
LD4 (flashing)	The high-pressure switch has tripped. 63H2 operation, investigate high-pressure causes or a disconnected switch. Steady LD4 = compressor running (normal).	🟡 Check the outdoor unit has clear space and airflow around it and the filters are clean, then book a service if the fault returns.
LD5 (flashing)	The compressor overcurrent relay tripped, the compressor is locked or pulling too much current. 51CM operation; power supply also worth checking. Steady LD5 = outdoor fan running (normal).	🔴 Switch the system off at the isolator and call for service.
LD6 (flashing)	The thermal switch tripped, can point to low refrigerant. 26C operation; check for low refrigerant level or a disconnected switch. Steady LD6 = 4-way (reversing) valve energised (normal).	🔴 Switch the system off at the isolator and call for service.
LD7 (flashing)	Coil overheat protection, the coil passed 67°C, usually from poor airflow at the outdoor unit. TH3 overheat protection; fan motor or thermistor faults are the cited causes. Steady LD7 = bypass valve open (normal).	🟡 Make sure the outdoor unit has clear space and airflow around it, then book a service if the fault returns.
LD8 (flashing)	The outdoor board's input circuit is defective. Source says replace the outdoor board. Steady LD8 = crankcase heater on (normal).	🟡 Book a service and quote the code.

City Multi VRF (R22 / R407C / R410A generations; includes BC controller and Lossnay-linked codes)

Where the code shows: Four-digit code on the local remote controller, central controller or outdoor unit service display. The source lists applicability per code by refrigerant generation (R22 / R407C / R410A) and for Lossnay units..

Tap your code: 0403 1102 1111 1112 1113 1202 1204 1205 1211 1214 1216 1217 1219 1221 1243 1301 1302 1368 1370 1402 1500 1501 1505 2500 2502 2503 2600 4100 4101 4102 4103 4106 4108 4115 4116 4124 4210 4220 4225 4230 4235 4240 4245 4250 4255 4260 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5201 5202 5203 5300 5301 5401 5701 6201 6202 6600 6601 6602 6603 6607 6608 6830 6831 6832 6833 6834 6840 6841 6844 6845 6846 7100 7101 7102 7105 7106 7107 7110 7111 7113 7117 7130

Code	What it means	What to do
0403	Two circuit boards inside the unit have stopped talking to each other over the serial link. Check the inverter error detail for which two boards; transformer, bus voltage and inter-board cables are the listed checks. Shown as 403 in the source.	🟡 Report the code to your service contractor, this needs a technician.
1102	The compressor's discharge gas passed 110°C, commonly a refrigerant shortage. A faulty discharge thermistor can also trigger it.	🔴 Switch the system off and call your service contractor straight away.
1111	Low refrigerant pressure/temperature fault. Listed checks: TH2/TH3/TH4 thermistors, gas charge, indoor fan, heat exchanger and filters. Source gives identical text for 1111, 1112 and 1113.	🔴 Switch the system off and call your service contractor straight away.
1112	Low refrigerant pressure/temperature fault. Listed checks: TH2/TH3/TH4 thermistors, gas charge, indoor fan, heat exchanger and filters. Source gives identical text for 1111, 1112 and 1113.	🔴 Switch the system off and call your service contractor straight away.
1113	Low refrigerant pressure/temperature fault. Listed checks: TH2/TH3/TH4 thermistors, gas charge, indoor fan, heat exchanger and filters. Source gives identical text for 1111, 1112 and 1113.	🔴 Switch the system off and call your service contractor straight away.
1202	Early warning of a high discharge-temperature fault (precursor to 1102).	🟡 Report the code to your service contractor, this needs a technician.
1204	Early warning fault on the heat-exchanger gas temperature sensors. Thermistors 10a and 10b.	🟡 Report the code to your service contractor, this needs a technician.
1205	Early warning fault on the TH5 pipe temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1211	Early warning fault on the TH2 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1214	Early warning fault on the inverter heat-sink temperature sensor. THHS thermistor.	🟡 Report the code to your service contractor, this needs a technician.
1216	Early warning fault on the TH7 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1217	Early warning fault on the TH8 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1219	Early warning fault on the TH9 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1221	Early warning fault on the TH6 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1243	Early warning fault on the TH10 temperature sensor.	🟡 Report the code to your service contractor, this needs a technician.
1301	Refrigerant pressure read under 1 bar just before start-up, low charge or a sensor fault. 63L operation detected via the low-pressure sensor.	🔴 Switch the system off and call your service contractor straight away.
1302	The system tripped on high refrigerant pressure. Trip thresholds about 29 bar (R407C) or 38 bar (R410A); the high-pressure sensor is compared against gauge pressure.	🟡 Report the code to your service contractor, this needs a technician.
1368	Pressure sensor PS1 at the BC controller is reading incorrectly. Compared against the outdoor unit's SW1 pressure display.	🟡 Report the code to your service contractor, this needs a technician.
1370	Pressure sensor PS3 at the BC controller is reading incorrectly. Compared against the outdoor unit's SW1 pressure display.	🟡 Report the code to your service contractor, this needs a technician.
1402	Early warning of a high-pressure fault (precursor to 1302).	🟡 Report the code to your service contractor, this needs a technician.
1500	The system has too much refrigerant in it, compressor superheat is abnormally low. Detected via the TH4 discharge thermistor.	🟡 Report the code to your service contractor, this needs a technician.
1501	The compressor shell is running hot, refrigerant shortage suspected. On computer-room systems, too little indoor capacity running can also cause it.	🔴 Switch the system off and call your service contractor straight away.
1505	Suction pressure abnormal, the compressor pulled a vacuum. Listed causes: a blockage, a closed service valve or a faulty low-pressure sensor.	🟡 Report the code to your service contractor, this needs a technician.
2500	Not enough water flow detected in the water circuit. Applies to water-circuit models.	🟡 Report the code to your service contractor, this needs a technician.
2502	Water is building up in the indoor unit's drain tray during cooling (temperature-sensor detection). Checks: sensor circuits open/closed and drain pump operation.	🟡 Report the code to your service contractor, this needs a technician.
2503	The drain tray float switch tripped, condensate is not draining away. Checks: float switch circuit and drain pump operation.	🟡 Report the code to your service contractor, this needs a technician.
2600	A water leak was detected from the humidifier.	🟡 Report the code to your service contractor, this needs a technician.
4100	Compressor overcurrent protection tripped on a Mr Slim unit connected via an M-NET interface. Inverter or compressor at fault.	🔴 Switch the system off and call your service contractor straight away.
4101	Compressor overcurrent protection tripped on a Mr Slim unit connected via an M-NET interface. Inverter or compressor at fault. Source gives identical text for 4100 and 4101.	🔴 Switch the system off and call your service contractor straight away.
4102	A supply phase is missing (open phase). Power supply, noise filter, wiring and fuse checks.	🟡 Report the code to your service contractor, this needs a technician.
4103	Supply phases are connected in the wrong order (reverse phase). Also flags a lost phase through the noise filter, a blown fuse, or the high-pressure switch open at power-on.	🟡 Report the code to your service contractor, this needs a technician.
4106	Fault in the transmission-line power supply. Wiring, high current, incorrect voltage on the transmission line, or the M-NET board.	🟡 Report the code to your service contractor, this needs a technician.
4108	Overcurrent trip on a direct-on-line compressor. Power supply, contactor and compressor checks.	🔴 Switch the system off and call your service contractor straight away.
4115	The power supply to the unit is abnormal. Power, fuses, connections and PCB checks.	🟡 Report the code to your service contractor, this needs a technician.
4116	Fan motor fault on an indoor or Lossnay unit. Fan motor and board checks.	🟡 Report the code to your service contractor, this needs a technician.
4124	The compressor's internal thermal switch circuit is open (Mr Slim unit on M-NET). 49C thermal switch; reset and check pressures and airflow.	🟡 Report the code to your service contractor, this needs a technician.
4210	Compressor overcurrent problem. Inverter balance, compressor and inverter checks.	🔴 Switch the system off and call your service contractor straight away.
4220	The inverter's DC bus voltage is too low (under about 289 V DC). Usually a mains supply issue.	🟡 Report the code to your service contractor, this needs a technician.
4225	DC voltage is too low on the fan inverter. Checks: about 300 V DC at the diode stack (CNVdc) and the mains supply to the outdoor unit.	🟡 Report the code to your service contractor, this needs a technician.
4230	The inverter's heat sink is overheating. Blocked air duct, failed inverter fan or a faulty thermistor.	🟡 Report the code to your service contractor, this needs a technician.
4235	The fan inverter's heat sink overheat protection tripped. Reduced airflow through the heat sink, a fan motor problem, or the THHS thermistor.	🟡 Report the code to your service contractor, this needs a technician.
4240	Overcurrent protection, high current sustained for more than 10 minutes. Inverter balance and heat-sink airflow checks.	🔴 Switch the system off and call your service contractor straight away.
4245	Overcurrent protection tripped, possibly a faulty current sensor. ACCT sensor; a healthy one reads about 280 ohm across pins 1–2 and 3–4.	🟡 Report the code to your service contractor, this needs a technician.
4250	Overcurrent protection, an inverter power-module fault or a locked compressor. IPM problem or compressor lock; inverter balance checks.	🔴 Switch the system off and call your service contractor straight away.
4255	Problem with the inverter's cooling fan. With a high-static fan fitted, switch SW3-9 must be on.	🟡 Report the code to your service contractor, this needs a technician.
4260	Early warning of inverter heat-sink overheating. Reduced heat-sink airflow, a fan motor problem, or the THHS thermistor.	🟡 Report the code to your service contractor, this needs a technician.
5101	A temperature sensor on an indoor or outdoor unit has failed. The fault-code address identifies which unit and sensor.	🟡 Report the code to your service contractor, this needs a technician.
5102	A temperature sensor on an indoor or outdoor unit has failed. The fault-code address identifies which unit and sensor.	🟡 Report the code to your service contractor, this needs a technician.
5103	A temperature sensor on an indoor or outdoor unit has failed. The fault-code address identifies which unit and sensor.	🟡 Report the code to your service contractor, this needs a technician.
5104	A temperature sensor on an indoor or outdoor unit has failed. The fault-code address identifies which unit and sensor. For indoor faults the source also says confirm switch SW7-3 is off.	🟡 Report the code to your service contractor, this needs a technician.
5105	Temperature sensor TH5 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5106	Temperature sensor TH6 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5107	Temperature sensor TH7 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5108	Temperature sensor TH8 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5109	Temperature sensor TH9 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5110	Temperature sensor TH10 is open or short circuit. Check whether the thermistor has come off the board.	🟡 Report the code to your service contractor, this needs a technician.
5111	BC controller temperature sensor TH11 is open or short circuit, or off its pipe.	🟡 Report the code to your service contractor, this needs a technician.
5112	A BC controller temperature sensor is open or short circuit, or off its pipe. The compendium prints 'TH10' here, a misprint: official City Multi service handbooks (PURY series) give 5112 as the bypass outlet temperature sensor (TH12) fault on the BC controller.	🟡 Report the code to your service contractor, this needs a technician.
5113	A BC controller temperature sensor is open or short circuit, or off its pipe. Sensor number not given in the source.	🟡 Report the code to your service contractor, this needs a technician.
5114	A BC controller temperature sensor is open or short circuit, or off its pipe. Sensor number not given in the source.	🟡 Report the code to your service contractor, this needs a technician.
5115	BC controller temperature sensor TH15 is open or short circuit, or off its pipe.	🟡 Report the code to your service contractor, this needs a technician.
5116	BC controller temperature sensor TH16 is open or short circuit, or off its pipe.	🟡 Report the code to your service contractor, this needs a technician.
5201	Pressure sensor fault at the outdoor unit or BC controller. SW1 pressure readouts compared against gauge, per the fault-code address.	🟡 Report the code to your service contractor, this needs a technician.
5202	Pressure sensor PS2 in the BC controller is faulty.	🟡 Report the code to your service contractor, this needs a technician.
5203	Pressure sensor PS3 in the BC controller is faulty.	🟡 Report the code to your service contractor, this needs a technician.
5300	A Mr Slim unit on the network reported a current-sensor (UH) fault. M-NET translation of the Mr Slim A-control UH code.	🟡 Report the code to your service contractor, this needs a technician.
5301	Current sensor fault on the inverter. ACCT or DCCT sensor; the inverter error details identify which.	🟡 Report the code to your service contractor, this needs a technician.
5401	Humidity/temperature sensor fault. Connector CN30 for the humidity sensor.	🟡 Report the code to your service contractor, this needs a technician.
5701	The drain-tray float switch connector has come loose. Float switch and connector CN4F on the indoor unit.	🟡 Report the code to your service contractor, this needs a technician.
6201	Communication error on the TB7 transmission line. Voltage abnormality or a short on the line.	🟡 Report the code to your service contractor, this needs a technician.
6202	Hardware error in the transmission processor. Electrical noise or a short on the M-NET cable.	🟡 Report the code to your service contractor, this needs a technician.
6600	Two or more units on the network have been given the same address. Fixed by correcting the repeated address.	🟡 Report the code to your service contractor, this needs a technician.
6601	Polarity or voltage problem on the M-NET transmission line. No voltage or a short circuit on the line.	🟡 Report the code to your service contractor, this needs a technician.
6602	Transmission processor hardware error, interference or a polarity problem on TB7.	🟡 Report the code to your service contractor, this needs a technician.
6603	The network bus is jammed, often something wired into TB7 that belongs on TB3.	🟡 Report the code to your service contractor, this needs a technician.
6607	A unit on the network stopped answering while the system was running. No response received back from the unit; often follows a power interruption.	🟢 If there has been a power interruption, turn the system off at the isolator, wait 20–30 minutes and restore power. If the code returns, call your service contractor.
6608	Network communication dropped out, voltage loss or electrical noise on the line.	🟢 If there has been a power interruption, turn the system off at the isolator, wait 20–30 minutes and restore power. If the code returns, call your service contractor.
6830	The indoor unit and MA remote controller are not communicating. Checks: controller connections, 12 V DC on the controller line, and that the controller is not set as a sub controller.	🟡 Report the code to your service contractor, this needs a technician.
6831	The MA remote controller is not receiving. Checks: TB15 connections; removing the controller while the indoor unit is powered can trigger it.	🟡 Report the code to your service contractor, this needs a technician.
6832	MA remote controller communication fault. Checks: cable length (max 500 m), cable type, connections, and the main/sub controller setting.	🟡 Report the code to your service contractor, this needs a technician.
6833	MA remote controller communication fault (transmitting side). Checks: cable length (max 500 m), cable type, connections, and the main/sub controller setting.	🟡 Report the code to your service contractor, this needs a technician.
6834	MA remote controller communication fault (receiving side). Checks: cable length (max 500 m), cable type, connections, and the main/sub controller setting.	🟡 Report the code to your service contractor, this needs a technician.
6840	A Mr Slim unit on the network reported an indoor/outdoor communication fault (its E6/E8 code). M-NET translation of Mr Slim A-control E6/E8.	🟢 If there has been a power interruption, turn the system off at the isolator, wait 20–30 minutes and restore power. If the code returns, call your service contractor.
6841	A Mr Slim unit on the network reported an indoor/outdoor communication fault (its E7/E9 code). M-NET translation of Mr Slim A-control E7/E9.	🟢 If there has been a power interruption, turn the system off at the isolator, wait 20–30 minutes and restore power. If the code returns, call your service contractor.
6844	A Mr Slim unit on the network reported a wiring/connection fault (its EA code). Mis-wiring, loose inter-connecting cables or interference. M-NET translation of Mr Slim A-control EA.	🟡 Report the code to your service contractor, this needs a technician.
6845	A Mr Slim unit on the network reported a wiring fault (its Eb code). Mis-wiring, loose cables, interference, or wrong cable size/spec. M-NET translation of Mr Slim A-control Eb.	🟡 Report the code to your service contractor, this needs a technician.
6846	A Mr Slim unit on the network failed to finish starting up in time (its EC code). Interference or wrong cable size/spec. M-NET translation of Mr Slim A-control EC.	🟢 If there has been a power interruption, turn the system off at the isolator, wait 20–30 minutes and restore power. If the code returns, call your service contractor.
7100	The total indoor unit capacity exceeds what the outdoor unit allows. Limits: 150% of index on R2 series, 130% on Y series.	🟡 Report the code to your service contractor, this needs a technician.
7101	A capacity setting switch is set wrong. SW2 on indoor units, SW5 on YHM-A outdoor units (SW3-10 on older equipment).	🟡 Report the code to your service contractor, this needs a technician.
7102	The number of connected units does not match what the system expects. M-NET voltage loss (short or break), no power at the BC controller, a wrong SW5 setting, or the wrong BC box type.	🟡 Report the code to your service contractor, this needs a technician.
7105	An outdoor unit or BC controller address is set wrong.	🟡 Report the code to your service contractor, this needs a technician.
7106	Attribute setting error. SW3-1 setting on a GUF (Lossnay heat-recovery) unit.	🟡 Report the code to your service contractor, this needs a technician.
7107	BC controller port setting error. Too much capacity on a single port, wiring/SW2 setting, a wrong SW14 setting, or wrong unit assignment when using multiple BC boxes.	🟡 Report the code to your service contractor, this needs a technician.
7110	Connection-count setting switch SW5-7 is set incorrectly.	🟡 Report the code to your service contractor, this needs a technician.
7111	The system expects a temperature sensor in a remote controller that is missing or has failed. SW1-1 on with no controllers fitted, or a faulty remote controller.	🟡 Report the code to your service contractor, this needs a technician.
7113	Function setting error, a wrong switch setting or wrong resistors fitted. SW5 setting or resistors on YHM-A units.	🟡 Report the code to your service contractor, this needs a technician.
7117	Model setting error, a switch or resistor configuration is wrong. SW5 setting or wrong resistors fitted.	🟡 Report the code to your service contractor, this needs a technician.
7130	Incompatible equipment is connected to the network. Example given: a split with a MAC-399 interface wired onto the TB5 line instead of TB7.	🟡 Report the code to your service contractor, this needs a technician.

M-NET central controller — Lossnay ventilation fault codes (A-series)

Where the code shows: Two-character code on the central controller; the matching 4-digit M-NET code and LED1 (green) / LED2 (red) flash counts are noted per code..

Tap your code: A0 A2 A3 A6 A7 A8

Code	What it means	What to do
A0	Two or more Lossnay ventilation units share the same network address. M-NET 6600. LED1 2 flashes / LED2 5 flashes. Fixed by re-addressing the units and resetting power.	🟡 Book a service and quote the code, this is a setup issue that needs a technician.
A2	Hardware fault in a Lossnay unit's transmission processor. M-NET 6602. LED1 2 flashes / LED2 5 flashes. Communication wiring or a Lossnay board fault.	🟡 Book a service and quote the code.
A3	The network line stayed busy, nothing could transmit for 8 minutes. M-NET 6603. LED1 2 flashes / LED2 5 flashes. Check M-NET connections (TB7/TB3).	🟡 Book a service and quote the code.
A6	Communication processor error, the Lossnay unit's address never got transmitted. M-NET 6606. LED1 2 flashes / LED2 5 flashes. Check M-NET voltage.	🟡 Book a service and quote the code.
A7	No acknowledgement signal came back over the network. M-NET 6607. LED1 2 flashes / LED2 5 flashes. Wiring range exceeded or a faulty M-NET converter.	🟡 Book a service and quote the code.
A8	A unit on the network stopped responding. M-NET 6608. LED1 2 flashes / LED2 5 flashes. Wiring range, a faulty converter or the wrong cable type.	🟡 Book a service and quote the code.

M-series residential (MSZ) — MSZ-AP hi-wall indoor unit blink codes (live faults)

Where the code shows: Blink count of the OPERATION INDICATOR lamp on the indoor unit's display (the top lamp). When a fault is detected the unit stops, the indoor fan switches off and the lamp blinks in bursts separated by a 2.5-second pause; count the flashes in one burst. Standard MSZ wireless remotes show no letter-number code, the blinks are the code. Extracted from the MSZ-AP15-71 VF/VG(K) service manuals; AU retail models MSZ-AP22-50VGD/VGKD are the same platform..

Tap your code: Blinking continuously (0.5 s on / 0.5 s off)2 blinks per burst 3 blinks per burst 4 blinks per burst 5 blinks per burst 6 blinks per burst 7 blinks per burst 14 blinks or more per burst Lamp stays lit but the outdoor unit will not run Top lamp lit and lower lamp blinking

Code	What it means	What to do
Blinking continuously (0.5 s on / 0.5 s off)	The indoor and outdoor units have stopped talking to each other, from a connection problem or a lost signal. Serial signal from the outdoor unit not received for 6 minutes. Also appears when an indoor unit that was once paired with a different outdoor-unit generation needs its stored history cleared (low-standby-power pairing note in the manual).	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the light blinks again, book a service.
2 blinks per burst	A temperature sensor inside the indoor unit (room air or coil sensor) is not reading properly. Indoor coil thermistor or room temperature thermistor open or short circuit, checked every 8 seconds during operation.	🟡 Book a service and quote the blink count.
3 blinks per burst	The indoor fan motor is not reporting its speed back, the fan or its drive has a problem. No rotational-frequency feedback signal during indoor fan operation.	🟡 Book a service and quote the blink count.
4 blinks per burst	The indoor unit's control board has an internal memory fault. Nonvolatile memory on the indoor electronic control PCB cannot be read; board replacement is the listed remedy.	🟡 Book a service and quote the blink count.
5 blinks per burst	The outdoor unit keeps tripping its compressor protection straight after starting. Compressor stopped by overcurrent protection or start-up failure protection 3 consecutive times within 1 minute of starting. A closed service (stop) valve is a listed check.	🔴 Switch the system off at the isolator and call for service.
6 blinks per burst	A temperature sensor in the outdoor unit is not reading properly. Outdoor thermistor open or short circuit during compressor operation (discharge, defrost, fin, board, ambient or heat-exchanger sensor; the outdoor unit's own board LED tells the technician which one).	🟡 Book a service and quote the blink count.
7 blinks per burst	The outdoor unit's control electronics have an internal memory fault. Nonvolatile memory of the inverter PCB or the outdoor electronic control PCB cannot be read.	🟡 Book a service and quote the blink count.
14 blinks or more per burst	The outdoor unit has a fault outside the standard list. Listed checks are the stop valve and the 4-way valve; the exact fault is pinned down with the failure mode recall function.	🟡 Book a service and quote the blink count.
Lamp stays lit but the outdoor unit will not run	The outdoor unit's control board cannot read its memory, so the outdoor unit refuses to start while the indoor unit looks normal. Same nonvolatile-memory fault as 7 blinks, indicated with the lamp lit instead; confirmed by the LED on the outdoor unit's boards.	🟡 Book a service and mention that the indoor light stays on while the outdoor unit never starts.
Top lamp lit and lower lamp blinking	Usually not a fault. On a multi-head (MXZ) system the rooms are asking for opposite modes, and on demand-response models the electricity network has temporarily capped the unit. MXZ: indoor units set to COOL (including DRY) and HEAT at the same time; the first unit started has priority. AU MUZ-VGD demand models show the same indication during a DRM 2 or DRM 3 demand-response event (AS/NZS 4755.3.1), which ends by itself.	🟢 On a multi-head system, set every indoor unit to the same mode on the remote. If your unit is on a demand-response program, wait for the event to end. If neither applies, book a service.

M-series residential (MSZ) — remote-control self-check (failure mode recall), indoor unit faults

Where the code shows: Service self-check run from the wireless remote: with power on, hold OPERATION SELECT and the TEMP up button while pressing RESET on the remote, release RESET, keep holding the other two for 3 seconds until every LCD segment shows, then point the remote at the unit and press OFF/ON. The stored fault replays as blink bursts (with beeps) on the indoor OPERATION INDICATOR lamp. IMPORTANT: blink counts in this mode differ from the live fault blinks, and the mode must be released afterwards (power off, power on, press RESET on the remote) or the unit cannot operate properly..

Tap your code: 1 blink per burst (recall mode)2 blinks per burst (recall mode)3 blinks per burst (recall mode)11 blinks per burst (recall mode)12 blinks per burst (recall mode)

Code	What it means	What to do
1 blink per burst (recall mode)	A room temperature sensor fault is stored in the unit's memory. Room temperature thermistor open or short circuit was detected during operation.	🟡 Book a service and quote the blink count.
2 blinks per burst (recall mode)	An indoor coil temperature sensor fault is stored in the unit's memory. Indoor coil thermistor (main or sub) open or short circuit was detected during operation.	🟡 Book a service and quote the blink count.
3 blinks per burst (recall mode)	A communication dropout between the indoor and outdoor units is stored in the unit's memory. Serial signal from the outdoor unit was not received for up to 6 minutes.	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the light blinks again, book a service.
11 blinks per burst (recall mode)	An indoor fan motor fault is stored in the unit's memory. No rotational-frequency feedback for 12 seconds after the indoor fan motor was operated.	🟡 Book a service and quote the blink count.
12 blinks per burst (recall mode)	An indoor control board memory fault is stored in the unit's memory. Nonvolatile memory of the indoor electronic control PCB could not be read; board replacement is the listed remedy.	🟡 Book a service and quote the blink count.

M-series residential (MSZ) — remote-control self-check (failure mode recall), outdoor unit faults

Where the code shows: Second stage of the same remote self-check: with the recall function active, press the TEMP up button so 25°C is set to interrogate the outdoor unit. Outdoor faults replay on the indoor OPERATION INDICATOR lamp as a 3-second ON (no beep) followed by the blink burst with beeps; it can take up to a minute to start. Counts differ from live fault blinks. Matching patterns also show on the outdoor inverter-board LED for technicians..

Tap your code: 1 blink per burst (outdoor recall)2 blinks per burst (outdoor recall)3 blinks per burst (outdoor recall)4 blinks per burst (outdoor recall)5 blinks per burst (outdoor recall)6 blinks per burst (outdoor recall)7 blinks per burst (outdoor recall)8 blinks per burst (outdoor recall)9 blinks per burst (outdoor recall)10 blinks per burst (outdoor recall)11 blinks per burst (outdoor recall)14 blinks per burst (outdoor recall)16 blinks per burst (outdoor recall)

Code	What it means	What to do
1 blink per burst (outdoor recall)	A communication fault at the outdoor unit's end is stored in memory. No usable signal from the inverter PCB for 3 minutes, or 30 consecutive corrupted frames (signal sent as 0, received as 1).	🟢 Turn the system off at the isolator, wait 20–30 minutes, then turn it back on. If the light blinks again, book a service.
2 blinks per burst (outdoor recall)	The compressor's overcurrent protection tripped repeatedly right after starting. Overcurrent cut-out operated 3 consecutive times within 1 minute of the compressor starting. Listed remedies: reconnect the compressor connector, inverter/compressor checks, stop valve.	🔴 Switch the system off at the isolator and call for service.
3 blinks per burst (outdoor recall)	An outdoor temperature sensor fault is stored in memory. A thermistor shorted or opened while the compressor ran (discharge, defrost, fin, board, ambient or outdoor heat-exchanger sensor; the outdoor board LED blink count 1 to 4 identifies which).	🟡 Book a service and quote the blink count.
4 blinks per burst (outdoor recall)	The inverter saw too much current going into its power module, or the compressor would not start cleanly. Large current into power module IC700 (outdoor LED 11 blinks), or distorted compressor current waveform, compressor start-up failure protection (outdoor LED 12 blinks).	🔴 Switch the system off at the isolator and call for service.
5 blinks per burst (outdoor recall)	The compressor ran too hot, which commonly points to low refrigerant. Discharge temperature thermistor exceeded 116°C and the compressor stopped; restart is allowed once it reads 100°C or less 3 minutes later. Listed checks: refrigerant circuit and amount, LEV (expansion valve).	🔴 Switch the system off at the isolator and call for service.
6 blinks per burst (outdoor recall)	The system tripped on high-pressure protection, detected through coil temperatures. Indoor coil thermistor over 70°C in HEAT mode, or defrost thermistor over 70°C in COOL mode. Listed checks: refrigerant circuit and amount, stop valve.	🟡 Check the filters are clean and the outdoor unit has clear space around it, then book a service if it happens again.
7 blinks per burst (outdoor recall)	The outdoor unit's power electronics ran too hot. Fin temperature thermistor on the inverter heat sink exceeded 75–86°C (AP25-60) / 75–80°C (AP71), or the board temperature thermistor exceeded 72–85°C / 70–75°C. Listed checks: around the outdoor unit, its air passage, the outdoor fan motor.	🟡 Make sure the outdoor unit has clear space and airflow around it, then book a service if the fault returns.
8 blinks per burst (outdoor recall)	The outdoor fan motor kept stopping just after start-up. Outdoor fan stopped 3 times in a row within 30 seconds of fan start-up. Listed checks: outdoor fan motor, inverter PCB.	🟡 Book a service and quote the blink count.
9 blinks per burst (outdoor recall)	Either the inverter board's memory failed, or there is a short circuit in the inverter power module or compressor windings. Outdoor board LED 5 blinks = nonvolatile memory cannot be read (replace inverter PCB); 6 blinks = interface short circuit at the power module (IC700) output / shorted compressor winding.	🔴 Switch the system off at the isolator and call for service.
10 blinks per burst (outdoor recall)	The compressor's discharge stayed abnormally cold, the refrigerant metering is not right. Discharge temperature thermistor read 50°C or less for 20 minutes. Listed checks: LEV (expansion valve), refrigerant circuit and amount.	🟡 Book a service and quote the blink count.
11 blinks per burst (outdoor recall)	The inverter cannot read its own electrical measurements. Bus-bar DC voltage cannot be detected normally (outdoor LED 8 blinks), or a compressor phase current cannot be detected (outdoor LED 9 blinks).	🟡 Book a service and quote the blink count.
14 blinks per burst (outdoor recall)	A closed service valve was detected, or the reversing (4-way) valve is not switching. Closed stop valve detected from compressor current (outdoor LED 14 blinks); 4-way valve fault detected from an abnormal indoor coil temperature (outdoor LED 16 blinks).	🔴 Switch the system off at the isolator and call for service.
16 blinks per burst (outdoor recall)	The refrigerant circuit is not behaving, a closed valve or air trapped in the system. Detected from indoor/outdoor thermistor temperatures and compressor current. Listed remedies: check for a gas leak in the connecting pipes, check the stop valve, outdoor refrigerant circuit checks.	🔴 Switch the system off at the isolator and call for service.

Code still showing after a reset? Mention the code and your system type when you book and our office can line up the right technician and likely parts before we arrive.

Book a service or call (02) 4760 0100 (24-hour line, Penrith & Blue Mountains).

Daikin fault codes explained

by AmpleJon | Aug 3, 2026

When your Daikin system stops and shows a code, that code is the system telling you roughly where the problem is. Roughly is the key word. A fault code points in a direction, it rarely names the exact fix. Find your system below, tap your code, and it will take you straight to what it means and what to do.

RA & SkyAir (residential and light-commercial: ducted, wall splits, multi-head, cassettes)

Where the code shows: Not stated per model in the source docs. Codes typically show on the wall controller or via the remote's diagnosis function..

Tap your code: A0 A1 A3 A5 A6 A7 A8 A9 AA AF AH AJ C1 C4 C5 C6 C7 C9 CA CC CJ E0 E1 E3 E4 E5 E6 E7 E8 E9 EA F3 F6 H0 H1 H3 H4 H5 H6 H7 H8 H9 J1 J2 J3 J4 J5 J6 J7 J8 J9 JA JC L0 L1 L3 L4 L5 L6 L8 L9 LA LC P1 P3 P4 PJ U0 U1 U2 U3 U4 U5 U6 U8 UA UJ

Code	What it means	What to do
A0	A safety device connected to the indoor unit has tripped and shut the system down. External protection device wired to the indoor unit terminal strip (T1-T2).	🟡 Book a service. An installer-fitted safety device has activated and needs checking.
A1	The indoor unit's main circuit board isn't working properly. Can occasionally be triggered by electrical interference rather than a genuinely failed board.	🟡 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
A3	The system can't clear its condensate water properly. The drain, drain pump or float switch has a problem. Blocked or badly sloped drain line, failed drain pump, or a stuck float switch.	🟡 Switch the unit off so water can't overflow, and book a service.
A5	The indoor coil is protecting itself: running too hot in heating, or starting to freeze up in cooling. Poor airflow is the usual cause. Clogged return-air filters are the classic trigger; a dirty coil or a coil-sensor fault can also cause it.	🟢 Clean or check the return-air filters and make sure vents aren't blocked, then power-cycle at the isolator (off 20 to 30 minutes). If it comes back, book a service.
A6	The indoor fan motor isn't running the way it should. Fan motor, or its wiring and connectors.	🟡 Book a service.
A7	The motor that moves the air-direction louvre has a fault. Swing flap motor or its cam/connector. The unit usually still heats and cools.	🟡 The system is generally fine to keep using. Book a service to have the louvre fixed.
A8	The unit detected a problem with its incoming power: too much current on the supply input. Supply voltage or wiring issue on the AC input side.	🔴 Switch the unit off at the isolator and call us. Power faults need proper checking before the unit runs again.
A9	The indoor unit's refrigerant control valve (electronic expansion valve) isn't operating correctly. Valve coil, its cabling, or the indoor board driving it.	🟡 Book a service.
AA	A heater inside the unit has overheated and tripped its safety cut-out. Heater overheat protection (26WH) activated.	🔴 Switch the unit off at the isolator and call us. Overheating faults shouldn't be left running.
AF	The humidifier section of the system has a fault, possibly with water leaking. Applies to models with a humidifier fitted; often drain-piping related.	🟡 Switch the unit off and book a service, especially if you can see any water.
AH	The built-in air-cleaning (dust collector) section has a fault. Dust-collecting element or its high-voltage supply, on models with a built-in air cleaner.	🟡 Clean or check the filters if your model's user manual shows how. If the code stays, book a service.
AJ	The indoor unit's circuit board doesn't know what capacity the unit is. This setting is normally done when a board is replaced. Capacity-setting adaptor missing after a PCB replacement, or a faulty board.	🟡 Book a service. A technician needs to set the board up correctly.
C1	Two circuit boards inside the indoor unit have stopped talking to each other. Transmission fault between the indoor main PCB and its sub PCB.	🟡 Power-cycle at the isolator (off 20 to 30 minutes). If the code returns, book a service.
C4	The temperature sensor on the indoor coil's liquid pipe isn't reading properly. Liquid-pipe heat exchanger thermistor.	🟡 Book a service.
C5	The temperature sensor on the indoor coil's gas pipe isn't reading properly. Gas-pipe heat exchanger thermistor.	🟡 Book a service.
C6	The indoor fan's speed sensor or its control circuitry has a fault. Fan PCB, capacity-setting adaptor connection, or a field-setting error.	🟡 Book a service.
C7	The motor that opens the unit's front panel has a fault. On models with a motorised front panel; drive motor or limit switch.	🟡 The unit may still run normally. Book a service.
C9	The sensor that measures the room air coming into the indoor unit isn't reading properly. Suction (return) air thermistor.	🟡 Book a service.
CA	The sensor that measures the air blowing out of the indoor unit isn't reading properly. Discharge air thermistor.	🟡 Book a service.
CC	The humidity sensor has a fault. On models fitted with a humidity sensor.	🟡 Book a service.
CJ	The temperature sensor inside the wall controller isn't reading properly. The system usually keeps running using the indoor unit's own sensor instead.	🟡 The unit generally keeps working. Book a service at your convenience.
E0	A protection device on the outdoor unit has tripped. Generic outdoor protection actuation; the specific device isn't identified by this code alone.	🟡 A single power-cycle at the isolator (off 20 to 30 minutes) is safe to try. If the code returns, book a service.
E1	The outdoor unit's main circuit board isn't working properly. Board fault or a bad connection on the indoor/outdoor interconnecting wiring.	🟡 Power-cycle at the isolator (off 20 to 30 minutes). If the code returns, book a service.
E3	The outdoor unit shut itself down because refrigerant pressure went too high. Often a dirty or obstructed outdoor coil, a failed high-pressure switch, or a restricted refrigerant circuit.	🟡 Check the outdoor unit isn't blocked by leaves, plants or stored items and has clear airflow, then power-cycle at the isolator (off 20 to 30 minutes). If it trips again, book a service.
E4	The outdoor unit shut down because refrigerant pressure dropped too low. This can mean refrigerant is escaping. Low-pressure switch actuation; causes include low refrigerant, a failed sensor, or a fan fault.	🔴 Switch the system off at the isolator and call us. Low refrigerant pressure needs a licensed technician.
E5	The compressor motor overheated or seized. Inverter compressor motor lock or overheat.	🔴 Switch the system off at the isolator and call us. Keep it off until it's been checked.
E6	The fixed-speed compressor motor drew too much current or locked up. STD compressor overcurrent/lock; a closed service valve is one listed cause.	🔴 Switch the system off at the isolator and call us.
E7	The outdoor fan motor isn't running the way it should. Motor, its wiring/connector, or something jammed in the fan.	🟡 From outside the unit (don't open it), check nothing like leaves or debris is stopping the outdoor fan, then power-cycle. If the code returns, book a service.
E8	The inverter compressor drew too much current. Compressor or inverter power-circuit fault.	🔴 Switch the system off at the isolator and call us.
E9	The outdoor unit's refrigerant control valve (electronic expansion valve) isn't operating correctly. Valve coil, disconnected connector, or the outdoor control board.	🟡 Book a service.
EA	The valve that switches the system between heating and cooling has a fault. Four-way (reversing) valve; can also be triggered by low refrigerant.	🟡 Book a service.
F3	The compressor's discharge line got too hot, so the system stopped to protect the compressor. Often a sign of low refrigerant or a restriction in the refrigerant circuit.	🔴 Switch the system off at the isolator and call us. Running with this fault risks compressor damage.
F6	Refrigerant pressure is running too high, often because the system has too much refrigerant in it. Refrigerant overcharge, or a disconnected outdoor sensor confusing the pressure control.	🟡 Book a service. Refrigerant charge can only be checked and corrected by a licensed technician.
H0	A sensor on the compressor isn't reading properly. Compressor sensor-system fault: disconnected harness or board fault.	🟡 Book a service.
H1	A room temperature sensor or the humidifier's air damper has a fault. Room temperature sensor or humidifier unit damper. The humidifier-damper side mainly applies to models with a built-in humidifier (such as Daikin's Ururu Sarara range); the room-sensor side applies generally.	🟡 Book a service.
H3	The high-pressure safety switch itself has a fault (a sensor problem, not necessarily a pressure problem). Switch, broken wire, connector or outdoor board.	🟡 Book a service.
H4	The low-pressure safety switch itself has a fault. Switch, broken wire, connector or outdoor board.	🟡 Book a service.
H5	The sensor that watches the compressor for overload isn't reading properly. Compressor motor overload thermistor or its connector.	🟡 Book a service.
H6	The sensor that tracks the compressor motor's position has a fault, so the compressor may struggle to start. Position-detection sensor, compressor cabling, or outdoor board.	🟡 Book a service.
H7	The outdoor fan motor is sending an abnormal signal back to its circuit board. Fan motor lead disconnection/short, or the motor's internal circuit.	🟡 Book a service.
H8	The sensor that measures the compressor's electrical current has a fault. Compressor input (CT) system: power transistor, reactor, or wiring.	🟡 Book a service.
H9	The outdoor air temperature sensor isn't reading properly. Outdoor air thermistor, its connection, or the outdoor board.	🟡 Book a service.
J1	A refrigerant pressure sensor isn't reading properly. Pressure sensor or its connector contact.	🟡 Book a service.
J2	The compressor's current sensor isn't reading properly. Current sensor, compressor, or outdoor board.	🟡 Book a service.
J3	The temperature sensor on the compressor's discharge pipe isn't reading properly. Discharge pipe thermistor or its connection.	🟡 Book a service.
J4	A sensor that tracks low-side refrigerant temperature isn't reading properly. Low-pressure-equivalent saturated temperature sensor system.	🟡 Book a service.
J5	The temperature sensor on the compressor's suction pipe isn't reading properly. Suction pipe thermistor or its connection.	🟡 Book a service.
J6	The outdoor coil's temperature sensor isn't reading properly. Heat exchanger thermistor or its connection.	🟡 Book a service.
J7	A refrigerant-circuit temperature sensor (liquid line) isn't reading properly. The source doc lists J7 and J8 both as liquid-line thermistors at different points of the circuit.	🟡 Book a service.
J8	A refrigerant-circuit temperature sensor (liquid pipe) isn't reading properly. The source doc lists J7 and J8 both as liquid-line thermistors at different points of the circuit.	🟡 Book a service.
J9	A refrigerant-circuit temperature sensor (gas line) isn't reading properly. Gas pipe thermistor or its connection.	🟡 Book a service.
JA	The high-pressure sensor isn't reading properly. Can also be the high and low pressure sensor connections swapped.	🟡 Book a service.
JC	The low-pressure sensor isn't reading properly. Can also be the high and low pressure sensor connections swapped.	🟡 Book a service.
L0	The inverter (the electronics that control compressor speed) has a fault. Inverter system fault; power supply capacity or power transistor listed among causes.	🟡 Book a service.
L1	The inverter circuit board has a fault. Inverter PCB, compressor wiring, fan motor or a blown fuse.	🟡 Book a service.
L3	The outdoor unit's electrical box is running too hot. Often hot air recirculating around the unit; can also be a fan or board fault.	🟡 Make sure the outdoor unit has clear space around it and isn't sitting in trapped hot air, then power-cycle at the isolator. If the code returns, book a service.
L4	The inverter's heat sink (cooling fin) is running too hot. Airflow recirculation around the unit, or a faulty fin thermistor.	🟡 Make sure the outdoor unit has clear space and airflow around it, then power-cycle at the isolator. If the code returns, book a service.
L5	The inverter shut down instantly on overcurrent, often a compressor winding or startup problem. DC-side instantaneous overcurrent: compressor coil short/disconnection or mechanical lock.	🔴 Switch the system off at the isolator and call us.
L6	The inverter shut down instantly on overcurrent at its output. AC-side instantaneous overcurrent. Causes listed include refrigerant overcharge, weak power supply, or a failing compressor.	🔴 Switch the system off at the isolator and call us.
L8	The inverter detected the compressor drawing too much current (overload). Compressor overload, or a break in the compressor coil wiring.	🔴 Switch the system off at the isolator and call us.
L9	The compressor failed to start, so the system's stall-prevention stopped it. Causes include a service valve left closed, wiring errors, or high standing pressure at startup.	🟡 Book a service.
LA	A power transistor in the inverter has a fault. Power transistor, compressor, or inverter board.	🟡 Book a service.
LC	The inverter board and the main control board have stopped talking to each other. Board-to-board transmission fault; can be triggered by electrical interference.	🟡 Power-cycle at the isolator (off 20 to 30 minutes). If the code returns, book a service.
P1	The incoming power is unbalanced or missing a phase. Mostly applies to three-phase units; can also be an inverter board fault.	🟡 Book a service. Supply problems need an electrician or technician.
P3	A temperature sensor inside the outdoor unit's electrical box isn't reading properly. Switch-box / reactor thermistor.	🟡 Book a service.
P4	The sensor on the inverter's heat sink isn't reading properly. Radiation fin temperature thermistor.	🟡 Book a service.
PJ	The outdoor unit's circuit board doesn't know what capacity the unit is. A setup step after a board replacement was missed. Capacity-setting adaptor missing or wrong, or field settings not done after a PCB swap.	🟡 Book a service.
U0	The system is short of refrigerant. Refrigerant shortage or a blockage/wrong piping mimicking one.	🔴 Switch the system off and call us. Refrigerant leaks need a licensed technician, and running the unit low can damage the compressor.
U1	The power supply phases are connected in the wrong order, or one phase is missing. Three-phase supply issue (reverse phase / open phase).	🟡 Book a service. Phase wiring must be corrected by an electrician or technician.
U2	The unit saw a power problem: a voltage dip or a momentary blackout. Power supply voltage abnormality or instantaneous power failure.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code keeps returning, book a service.
U3	The system's commissioning test run was never completed. Check operation not executed.	🟡 Book a service. The installer needs to run the system's check operation.
U4	The indoor and outdoor units have lost communication with each other. Classic after a blackout or power interruption; can also be interconnecting wiring or a board fault.	🟢 Power-cycle at the isolator (off 20 to 30 minutes). If the units still won't talk to each other, book a service.
U5	The indoor unit and the wall controller have lost communication. Can also occur if two controllers are both set as 'main', or from electrical interference.	🟢 Power-cycle at the isolator (off 20 to 30 minutes). If the controller still won't connect, book a service.
U6	Indoor units on the same system have lost communication with each other. Applies to multi-unit setups (e.g. multi-head).	🟢 Power-cycle the whole system at the isolator (off 20 to 30 minutes). If the code returns, book a service.
U8	The main and secondary wall controllers aren't communicating, or their main/sub settings clash. Transmission error between main and sub remote controllers.	🟡 A power-cycle at the isolator is safe to try. If the code stays, book a service to have the controller settings corrected.
UA	The indoor and outdoor units aren't a valid match: wrong model pairing, wrong refrigerant type, or a setup step was missed. Also covers too many indoor units connected on multi systems.	🟡 Book a service.
UJ	An accessory device connected to the system isn't communicating properly. Attached/accessory equipment fault or its wiring.	🟡 Book a service.

VRV (commercial multi-split). Outdoor/system codes; indoor-unit codes on VRV match the RA & SkyAir list.

Where the code shows: Indoor wall controllers show the main code; the 2026 doc adds sub-codes (Master/Sub1/Sub2) read from the outdoor unit for technicians..

Tap your code: E1 E3 E4 E5 E7 E9 EA F3 F6 H7 H9 J2 J3 J4 J5 J6 J7 J8 J9 JA JC JE JF L1 L4 L5 L8 L9 LC M1 M8 MA MC P1 P4 U0 U1 U2 U3 U4 U5 U7 U8 U9 UA UC UE UF UH UJ

Code	What it means	What to do
E1	The outdoor unit's main circuit board isn't working properly.	🟡 Book a service with your service company.
E3	The system shut itself down because refrigerant pressure went too high. 2026 sub-codes point to closed stop valves, refrigerant overcharge, blocked airflow over the coil, or a pressure-switch/connector fault.	🟡 Make sure the outdoor units have clear airflow around them, then book a service.
E4	Refrigerant pressure dropped too low. This can mean a refrigerant shortage or service valves left closed. 2026 sub-codes cover closed stop valves, refrigerant shortage, and reversed gas-pipe connections at BS units.	🔴 Switch the system off and call your service company.
E5	The compressor motor overheated or seized.	🔴 Switch the system off and call your service company.
E7	An outdoor fan motor isn't running the way it should.	🟡 Book a service.
E9	An electronic expansion valve in an outdoor or BS unit isn't operating correctly. 2026 sub-codes identify which valve (Y1E through Y8E) and which board connector is affected.	🟡 Book a service.
EA	The valve that switches the system between heating and cooling has a fault. Four-way (reversing) valve or cool/heat switching.	🟡 Book a service.
F3	The compressor's discharge temperature got too high, so the system stopped to protect itself. 2026 sub-codes: closed stop valves, refrigerant shortage, or reversed gas-pipe connections at BS units.	🔴 Switch the system off and call your service company.
F6	Refrigerant pressure is running too high, often from an overcharged system or closed stop valves.	🟡 Book a service.
H7	An outdoor fan motor is sending an abnormal signal back to its circuit board.	🟡 Book a service.
H9	The outdoor air temperature sensor isn't reading properly.	🟡 Book a service.
J2	The compressor's current sensor isn't reading properly.	🟡 Book a service.
J3	A discharge-pipe temperature sensor isn't reading properly. 2026 sub-codes identify the specific sensor (R15T/R17T etc.) and board connector.	🟡 Book a service.
J4	A sensor that tracks low-side refrigerant temperature isn't reading properly. Low-pressure-equivalent saturated temperature sensor system.	🟡 Book a service.
J5	A suction-pipe temperature sensor isn't reading properly. 2026 doc lists multiple sensor/connector sub-codes for this family.	🟡 Book a service.
J6	A heat-exchanger (coil) temperature sensor isn't reading properly.	🟡 Book a service.
J7	A refrigerant-circuit temperature sensor (liquid line) isn't reading properly. 2026 sub-codes identify the specific thermistor and board connector.	🟡 Book a service.
J8	A refrigerant-circuit temperature sensor (liquid pipe) isn't reading properly.	🟡 Book a service.
J9	A refrigerant-circuit temperature sensor (gas line) isn't reading properly. 2026 sub-codes identify the specific thermistor and board connector.	🟡 Book a service.
JA	The high-pressure sensor isn't reading properly. 2026 sub-codes distinguish open-circuit vs short-circuit of sensor S1NPH.	🟡 Book a service.
JC	The low-pressure sensor isn't reading properly. 2026 sub-codes distinguish open-circuit vs short-circuit of sensor S1NPL.	🟡 Book a service.
JE	The oil pressure sensor (or a sub-tank temperature sensor) has a fault.	🟡 Book a service.
JF	The oil level sensor (or a heating heat-exchanger temperature sensor) has a fault.	🟡 Book a service.
L1	An inverter circuit board has a fault.	🟡 Book a service.
L4	The inverter's heat sink is running too hot. Often airflow recirculation around the outdoor units.	🟡 Make sure the outdoor units have clear space and airflow, then book a service if the code returns.
L5	The inverter shut down instantly on overcurrent, often a compressor winding or startup problem.	🔴 Switch the system off and call your service company.
L8	The inverter detected a compressor drawing too much current (overload).	🔴 Switch the system off and call your service company.
L9	A compressor failed to start, so stall-prevention stopped the system. Causes include closed service valves, wiring errors, or high standing pressure at startup.	🟡 Book a service.
LC	Circuit boards inside the outdoor unit (inverter, fan and control boards) have lost communication with each other. The 2026 doc lists board-to-board transmission sub-codes (e.g. A3P-A8P, A4P-A3P connections).	🟡 A power-cycle at the isolator (off 20 to 30 minutes) is safe to try. If the code returns, book a service.
M1	The central remote controller's circuit board has a fault.	🟡 Book a service.
M8	Centralised control devices have lost communication with each other. Can be power loss to one controller, transmission wiring, or an address change.	🟡 Book a service.
MA	The centralised controllers are combined in a way the system doesn't allow, for example two set as master.	🟡 Book a service.
MC	Two centralised controllers have been given the same address.	🟡 Book a service.
P1	The incoming power is unbalanced or missing a phase, or the inverter board has failed. 2026 doc: unbalanced supply voltage, voltage shortage or open phase.	🟡 Book a service. Supply problems need an electrician or technician.
P4	The sensor on the inverter's heat sink isn't reading properly.	🟡 Book a service.
U0	The system is short of refrigerant. Refrigerant shortage, or a blockage/wrong piping mimicking one.	🔴 Switch the system off and call your service company. Running low on refrigerant can damage the compressors.
U1	The power supply phases are connected in the wrong order, or one phase is missing. 2026 doc: reversed or open power supply phase; correct the phase order.	🟡 Book a service. Phase wiring must be corrected by an electrician or technician.
U2	The system saw a power problem: a voltage dip or a momentary blackout. 2026 doc: check the power supply is within range.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code keeps returning, book a service.
U3	The system's commissioning test run hasn't been completed, or it failed part-way through. 2026 sub-codes cover: test run not executed, aborted on error, aborted on communication issues, mis-wiring, or a fault on a connected indoor unit.	🟡 Book a service. The installer needs to complete the system test run.
U4	The outdoor unit has lost communication with its indoor units. Classic after a power interruption. 2026 sub-codes also cover mis-wired F1/F2 transmission lines and faults on connected indoor units.	🟢 Power-cycle at the isolator (off 20 to 30 minutes). If communication doesn't come back, call your service company.
U5	An indoor unit and its wall controller have lost communication. Can also occur if two controllers are both set as main.	🟢 Power-cycle at the isolator (off 20 to 30 minutes). If the controller still won't connect, book a service.
U7	Outdoor units on the same system have lost communication with each other. Transmission wiring between outdoor units or to an external control adaptor.	🟡 Book a service.
U8	The main and secondary wall controllers aren't communicating, or their main/sub settings clash.	🟡 Book a service.
U9	Another indoor or BS unit on the same refrigerant system has a fault, and it's stopping this unit too.	🟡 Check the other units on the system for their own fault codes, and book a service.
UA	The mix of indoor, BS and outdoor units isn't a valid combination, or too many indoor units are connected. 2026 sub-codes cover model/series mismatches, refrigerant-type mismatches, BS-unit combinations, wiring position errors and DIP-switch settings.	🟡 Book a service.
UC	Two devices on the centralised control network have been given the same address.	🟡 Book a service.
UE	An indoor unit has lost communication with the centralised controller.	🟡 Book a service.
UF	The system's wiring check found problems, or its automatic addressing didn't complete. 2026 sub-codes: auto-address inconsistency, wrong wiring between indoor and BS units, or stop valves left closed.	🟡 Book a service.
UH	The system hasn't finished sorting out its unit addressing: the number of wired and powered units don't match, or initialisation is still running. 2026 doc: auto-address malfunction (inconsistency); check unit counts or wait for initialisation to finish.	🟡 If the system was just powered up, give it time to finish initialising. If the code stays, book a service.
UJ	An accessory device connected to the system isn't communicating properly.	🟡 Book a service.

Code still showing after a reset? Mention the code and your system type when you book and our office can line up the right technician and likely parts before we arrive.

Book a service or call (02) 4760 0100 (24-hour line, Penrith & Blue Mountains).

MyAir & MyPlace status codes (Advantage Air)

by AmpleJon | Aug 3, 2026

When your Advantage Air system stops and shows a code, that code is the system telling you roughly where the problem is. Roughly is the key word. A fault code points in a direction, it rarely names the exact fix. Find your system below, tap your code, and it will take you straight to what it means and what to do.

MyAir / MyPlace / e-zone / Zone 10e wall touchscreens – remote access and connectivity statuses (AA20-AA32)

Where the code shows: Wall-mounted touchscreen: Setup > Remote Access screen (status field); AA30-AA32 relate to the connection from the phone app.

Tap your code: AA20 AA21 AA22 AA23 AA24 AA25 AA26 AA27 AA28 AA29 AA30 AA31 AA32

Code	What it means	What to do
AA20	Remote access can't get a connection from the wall touchscreen, so controlling the system from outside your home won't work. Advantage Air's current status-code page lists AA20 as a general remote connection error; the older MyPlace manual (V1.3) described it as the touchscreen having no internet access. In-home WiFi control can still work without internet.	🟢 Check the touchscreen is connected to your home WiFi and the internet is working, and restart your router. Then turn remote access off and on in the AA Service app on the wall touchscreen and reboot the touchscreen. If the code changes to AA26, remote access is back (you may need to re-pair your phone on the home WiFi). If it won't clear, call Advantage Air on 1300 850 191.
AA21	The touchscreen tried to set up remote access but the connection attempt failed. Remote connection error, usually a temporary network or server-side hiccup.	🟢 Reboot the wall touchscreen and give it about 10 minutes, then check the status again. If it keeps failing, call Advantage Air on 1300 850 191 or your installer.
AA22	Remote access was working, but the wall touchscreen has since dropped off the internet. Tablet lost its internet connection after remote access was previously established. Official wording: 'Your wall mounted touch screen is no longer connected to internet.'	🟢 In the touchscreen's settings check WiFi is on and connected to your home network, and re-enter the WiFi password if needed. If it's connected but has no internet, restart your router. Still stuck: turn remote access off and on in your Advantage Air app, then call 1300 850 191 if the code stays.
AA23	The wall touchscreen isn't connected to any WiFi network at all. Differs from AA22: AA22 is connected to WiFi but has no internet, AA23 has no WiFi network connected.	🟢 Open the touchscreen's WiFi settings and connect it to your home WiFi network. If it won't connect, restart your router and try again.
AA24	The wall touchscreen itself has hit an internal error. Official wording: 'Error has occurred with your wall mounted touch screen. Please reset the touch screen and call Advantage Air.'	🟡 Reboot the wall touchscreen, then call Advantage Air on 1300 850 191 or book a service if the code comes back.
AA25	Remote access is still starting up. Not a fault, just wait. Startup status; enabling remote access can take up to 5 minutes before it settles on AA26.	🟢 Nothing to fix. Give it a few minutes and the status should change to AA26 (working).
AA26	Normal status, remote access is set up correctly and should be working. This is the code you want to see. Success status, not a fault. Shown once remote access has enabled (can take up to 5 minutes after switching it on).	🟢 Nothing to fix. If the phone app still won't connect from outside the home, connect your phone to the home WiFi with the MyPlace app open for about 10 seconds to re-pair, then try again.
AA27	Remote access hit a connection error between the touchscreen and Advantage Air's servers. Same fix path as AA20.	🟢 Check the touchscreen has internet, restart your router, turn remote access off and on in the AA Service app on the wall touchscreen, then reboot the touchscreen.
AA28	The remote access server is busy right now. Server-side congestion, nothing wrong at your end.	🟢 Reboot the wall touchscreen and try again in about 10 minutes.
AA29	Remote access hit a connection error that needs Advantage Air's help desk to sort out. Official fix is simply to record the code and call the help desk; a reboot first costs nothing.	🟢 Reboot the wall touchscreen. If the code stays, write it down and call Advantage Air on 1300 850 191.
AA30	Your phone can't reach the system remotely, usually because the phone itself has no working internet. Mobile-side remote connection error (official steps reference an Android device).	🟢 Check your phone is on mobile data or WiFi and can load a web page in the browser. If the phone has internet but the code stays, call Advantage Air on 1300 850 191.
AA31	The remote access server is busy right now (shown on the phone side). Same as AA28: server-side congestion.	🟢 Reboot the wall touchscreen and try again in about 10 minutes.
AA32	A remote connection error that needs Advantage Air's help desk to sort out. Same handling as AA29.	🟢 Reboot the wall touchscreen. If the code stays, write it down and call Advantage Air on 1300 850 191.

MyAir 5 / MyPlace (CB7 control box + zone temperature sensors)

Where the code shows: Wall touchscreen: low-battery warning on the Zones page (older versions: home screen), AA8x sensor status codes in the Setup status window, full per-zone sensor status in the installer's Tech Setup > Temperature Sensors screen.

Tap your code: Battery Low Multiple sensors on this zone Sensor not displayed for a zone AA4 AA81 / AA82 / AA83 AA84 / AA85 / AA86 AA87 / AA88 / AA89

Code	What it means	What to do
Battery Low	A wireless zone temperature sensor's battery is running flat, so that zone's temperature reading may drop out. Applies to RF wall sensors. The installer-side check also covers the control-box antenna and sensor radio range. Shown as status codes AA84-AA86 on the status-code lookup.	🟢 Replace the battery in that zone's wall sensor. If the warning stays after a fresh battery, book a service.
Multiple sensors on this zone	The system is seeing more than one temperature sensor assigned to the same zone, occasionally it is actually picking up a neighbour's system on the same ID. Fix involves re-setting sensor zone switches or changing the System ID dipswitch inside the control box, which is an installer job. Shown as status codes AA87-AA89 on the status-code lookup.	🟡 Book a service, this needs sensor and system ID settings changed at the control box.
Sensor not displayed for a zone	The system isn't detecting a temperature sensor for that zone, so the zone falls back to plain airflow (%) control instead of temperature control. Screen state rather than a literal message: the zone simply shows no sensor on the Temperature Sensors screen. Causes include battery pull-tab still fitted, battery in wrong way, wrong System ID, or two sensors set to one zone.	🟢 If that zone has a wireless wall sensor, check its battery is fitted correctly (and any pull-tab removed on a new install). If the zone still shows percentage-only control, book a service.
AA4	The system can't find any of its zone temperature sensors. Official wording: 'System is not detecting any temperature sensors.' The current AU fix checklist covers sensor System ID (Setup > Advanced Info), one zone dip switch per sensor, and battery connections; the older End User PDF just gives the general mains reset.	🟡 Check the batteries in your wireless wall sensors, then power-cycle the system at the mains (off 15 minutes, then allow 5 minutes after restarting). If sensors still don't show up, book a service; the remaining checks are installer settings.
AA81 / AA82 / AA83	A wireless wall sensor is talking to the system but its zone assignment is wrong: either no zone allocated, or more than one zone set on the same sensor. Zone allocation is set by dip switches in the sensor and the System ID, which is installer configuration. The NZ page notes the air conditioner should still run in the meantime.	🟡 Write down the code and book a service; the zone allocation needs to be corrected by an installer. Your system should keep working in the meantime.
AA84 / AA85 / AA86	A wireless wall sensor has a low battery. NZ page fix: swap the battery with one from another sensor and wait an hour to confirm the warning follows the battery. The current AU page lists only AA86 and pairs it with the generic sensor checklist. Same underlying warning as the 'Battery Low' message above.	🟢 Replace the battery in the flagged wall sensor and give the system up to an hour to clear the warning. If it stays after a fresh battery, book a service.
AA87 / AA88 / AA89	The system is seeing more than one temperature sensor on the same zone. Same condition as the 'Multiple sensors on this zone' installer-screen status. Official first step is a mains power reset; the lasting fix is sensor dip switch / System ID configuration, an installer job. The current AU page lists only AA89.	🟡 Give it 5 minutes, then power-cycle the system at the mains (off 15 minutes, then allow 5 minutes after restarting). If the code returns, book a service so the sensor settings can be corrected.

MyAir 3/4/5 / MyPlace / e-zone / Zone 10e wall touchscreens – system and unit communication errors

Where the code shows: Wall-mounted touchscreen (status code shown on screen and in the phone app).

Tap your code: AA1 AA2 AA3 AA5 AA7 AA8 AA44

Code	What it means	What to do
AA1	The Advantage Air control gear has lost communication with the air-conditioning unit itself. Official wording: 'Communication error between Advantage Air componentry and A/C unit.' Classic after a blackout or brownout.	🟢 Give it 5 minutes to clear on its own. If not, power-cycle at the mains switch in your meter box (off 15 minutes), then allow 5 minutes after the touchscreen restarts before testing. If the code returns, book a service.
AA2	The system has detected more than one unit controller talking to it. Official wording: 'Multiple unit controllers detected.' Usually a commissioning or configuration clash.	🟡 Try one power-cycle at the mains (off 15 minutes, allow 5 minutes after restart). If the code comes back, book a service; this is a configuration issue for the installer.
AA3	A general communication error inside the Advantage Air system. Official wording is simply 'Communication error'.	🟢 Give it 5 minutes to clear on its own. If not, power-cycle at the mains (off 15 minutes, allow 5 minutes after restart). If the code returns, book a service.
AA5	The Advantage Air system and the air-conditioning unit have mismatched settings. Official wording: 'Mismatched unit settings.' A commissioning-level configuration issue.	🟡 Try one power-cycle at the mains (off 15 minutes, allow 5 minutes after restart). If the code comes back, book a service.
AA7	A configuration mismatch the system labels 'WSW mismatch'. Advantage Air's published description is just 'WSW mismatch' with the general reset steps; they don't expand the abbreviation publicly.	🟡 Try one power-cycle at the mains (off 15 minutes, allow 5 minutes after restart). If the code comes back, book a service.
AA8	The connected air-conditioning unit isn't compatible with how the system has been integrated. Official wording: 'Incompatible unit integration.'	🟡 Try one power-cycle at the mains (off 15 minutes, allow 5 minutes after restart). If the code comes back, book a service; the unit integration needs an installer.
AA44	The wall touchscreen has lost communication with the control box in the roof. The End User PDF also asks for AA Service V2 to be updated via the PlayStore before the reset; the current AU page just gives the general reset then installer.	🟢 Update the AA Service app in the PlayStore on the wall touchscreen if you can, then power-cycle at the mains (off 5-15 minutes, allow 5 minutes after restart). If the code stays, book a service or call 1300 850 191.

MyAir 3/4/5 / MyPlace / e-zone / Zone 10e wall touchscreens – activation lock

Where the code shows: Wall-mounted touchscreen.

Tap your code: AA9 AA52 / AA53

Code	What it means	What to do
AA9	The system's activation code has expired, so it won't run until a new code is entered. Tied to the dealer-set activation lock-out used at commissioning (see extraction notes on the 21-day lock-out in the MyAir manuals).	🟢 Ask your installer for the activation code, then enter it on the wall touchscreen. If you can't reach your installer, call Advantage Air on 1300 850 191.
AA52 / AA53	The system is asking for an activation code before it will run. Same activation lock family as AA9; the code comes from the installing company.	🟢 Ask your installer for the activation code and enter it on the wall touchscreen.

MyAir 3/4/5 / MyPlace / e-zone / Zone 10e wall touchscreens – installation and commissioning errors

Where the code shows: Wall-mounted touchscreen.

Tap your code: AA10 / AA11 / AA12 / AA13 AA14 AA60 / AA62 – AA69 AA122T

Code	What it means	What to do
AA10 / AA11 / AA12 / AA13	An installation or commissioning problem the system can't resolve on its own. The current AU page labels AA10/AA11 'Commissioning or Setup Error'; the End User PDF and NZ page label AA10-AA13 'Installation issue'. Only AA10 and AA11 remain on the current AU page.	🟡 Book a service; this one needs your installer.
AA14	A connection error that needs Advantage Air's help desk to diagnose. Official fix is simply to contact the help desk.	🟡 Call Advantage Air on 1300 850 191 and quote the code, or book a service.
AA60 / AA62 – AA69	A commissioning or setup error from the original installation. Current AU page: AA60 and AA62-AA68 'Commissioning or Setup Error'; End User PDF covers AA60, AA62-AA65 as 'Installation Issue'; AA69 appears only on the NZ page with the same meaning. AA61 is not published anywhere.	🟡 Book a service; this one needs your installer.
AA122T	The dip switches on an RM2 relay module are set incorrectly. RM2 is the Advantage Air Relay Module 2 used for MyPlace accessories (blinds, garage doors, etc.). Dip switch settings are installer configuration.	🟡 Book a service; the relay module settings need an installer.

MyAir 3/4/5 / MyPlace / e-zone / Zone 10e wall touchscreens – app update and AA Service statuses

Where the code shows: Wall-mounted touchscreen or the phone app, depending on which device is out of date.

Tap your code: AA33 AA34 AA35 AA36 / AA37 AA38 AA39 AA40 AA41 AA70 AA73 / AA74 AA75 AA76 / AA79 AA77 / AA78 / AA80

Code	What it means	What to do
AA33	The apps on the wall touchscreen are out of date. Official update path: PlayStore on the touchscreen, update (never fresh-install) the control app (MyPlace, MyAir 4, Ezone or Zone 10e as applicable) plus AA Service and, if present, AA Waca, then reboot.	🟢 Connect the touchscreen to the internet, open the PlayStore on it and update the Advantage Air apps (update only, don't install new ones), then reboot the touchscreen. If the code won't clear, call 1300 850 191.
AA34	The AA Waca app on the wall touchscreen is out of date. AA Waca is one of Advantage Air's background service apps on the touchscreen.	🟢 On the wall touchscreen, open the PlayStore, search for AA Waca and press update.
AA35	The MyPlace app is out of date. Applies to the wall touchscreen and any phones or tablets running the MyPlace app.	🟢 Update the MyPlace app on the wall touchscreen (PlayStore) and on your phones (PlayStore or App Store).
AA36 / AA37	The apps on a MyAir 5 wall touchscreen need upgrading. Same PlayStore update procedure as AA33 (control app + AA Service + AA Waca, update only, then reboot).	🟢 On the touchscreen, open the PlayStore and update the Advantage Air apps (update only, don't install new ones), then reboot it. If the code won't clear, call 1300 850 191.
AA38	The Advantage Air app on your Apple device is out of date. Covers MyPlace, MyAir 4, Ezone or Zone 10e apps on iPhone/iPad.	🟢 Open the App Store on your Apple device and update your Advantage Air app.
AA39	The Advantage Air app on your Android device is out of date. Covers MyPlace, MyAir 4, Ezone or Zone 10e apps on Android phones/tablets.	🟢 Open the PlayStore on your Android device and update your Advantage Air app.
AA40	The AA Service app has just been updated and the touchscreen needs a reboot to finish. Not a fault, just a pending restart.	🟢 Press and hold the power button on the wall touchscreen and choose reboot.
AA41	The touchscreen is still running version 1 of the AA Service app and needs version 2 installed. Official self-service path: advantageair.com.au/update4/ walks through installing AA Service V2.	🟢 Follow the steps at advantageair.com.au/update4 on the wall touchscreen, or call Advantage Air on 1300 850 191 for a hand.
AA70	The AA Service app's permissions aren't set correctly, and the system won't run until they are. Official wording: 'AA Service permissions are not set correctly. Your air-conditioning system will not run until they have been set correctly.'	🟢 Open the AA Service app on the wall touchscreen and enable its permissions when prompted. If the system still won't run, call 1300 850 191.
AA73 / AA74	The wall touchscreen needs app updates. Same PlayStore procedure: update the control app (MyPlace, e-zone, Zone 10e or MyAir 4), update only, then reboot.	🟢 On the touchscreen, open the PlayStore and update your Advantage Air control app, then reboot the touchscreen. If the code won't clear, call 1300 850 191.
AA75	The Advantage Air app on your iPhone needs updating. Covers MyPlace, e-zone, Zone 10e or MyAir 4 on iPhone.	🟢 Update your Advantage Air app from the App Store on your iPhone.
AA76 / AA79	The Advantage Air app on your Android phone needs updating. Covers MyPlace, e-zone, Zone 10e or MyAir 4 on Android.	🟢 Update your Advantage Air app from the PlayStore on your Android phone.
AA77 / AA78 / AA80	The apps on the wall touchscreen are out of date. Update set for these codes: MyPlace, AA Service and (if present) AA Waca, update only, then reboot.	🟢 On the touchscreen, open the PlayStore and update the Advantage Air apps (update only, don't install new ones), then reboot the touchscreen. If the code won't clear, call 1300 850 191.

MyAir 3/4/5 / MyPlace / e-zone / Zone 10e wall touchscreens – phone pairing and discovery

Where the code shows: Phone app (MyPlace / MyAir / e-zone / Zone 10e) or the wall touchscreen.

Tap your code: AA42 AA43 AA45 AA46 AA48 AA49 AA50 AA71 / AA72

Code	What it means	What to do
AA42	Your Apple device can't find the wall touchscreen on the network. Usually a WiFi mismatch or outdated apps on the touchscreen.	🟢 Check the touchscreen's apps are up to date (PlayStore on the touchscreen) and that it's on your home WiFi, then connect your Apple device to the same WiFi and try again. Rebooting the touchscreen also helps. If the code stays, call 1300 850 191.
AA43	Your Android device can't find the wall touchscreen on the network. Same handling as AA42.	🟢 Check the touchscreen's apps are up to date and that it's on your home WiFi, then connect your Android device to the same WiFi and try again. Rebooting the touchscreen also helps. If the code stays, call 1300 850 191.
AA45	The phone app hit a communication error reaching the system. The current AU page adds a first step: make sure mobile data is enabled for the Advantage Air app in your phone's settings.	🟢 Check mobile data is allowed for the app in your phone settings, check the touchscreen's WiFi, then reboot the touchscreen and your router and reconnect through the app. If the code stays, call 1300 850 191.
AA46	The phone app hit a communication error reaching the system (Android side). Same as AA45 but the reboot list adds the Android device itself.	🟢 Check mobile data is allowed for the app in your phone settings, check the touchscreen's WiFi, then reboot the touchscreen, your router and your Android phone and reconnect through the app. If the code stays, call 1300 850 191.
AA48	The wall touchscreen hasn't been paired with your Apple device yet. Pairing happens automatically while the app controls the system on the same WiFi.	🟢 Connect your Apple device to the same WiFi as the touchscreen, open your Advantage Air app and control the system for at least 10 seconds, then leave the WiFi and test remote access. If it won't pair, call 1300 850 191.
AA49	The wall touchscreen hasn't been paired with your Android device yet. Same pairing procedure as AA48.	🟢 Connect your Android device to the same WiFi as the touchscreen, open your Advantage Air app and control the system for at least 10 seconds, then leave the WiFi and test remote access. If it won't pair, call 1300 850 191.
AA50	The Advantage Air app on your Apple device has spotted a new system it doesn't recognise. For genuine multi-system homes the app must be switched from single-system to multiple-systems mode in iOS Settings.	🟢 If you do have more than one system: open Settings on your Apple device, find your Advantage Air app and switch the toggle from single to multiple systems. If you only have one system, call 1300 850 191.
AA71 / AA72	Your phone is trying to connect over mobile data but has no systems saved in the app, so there's nothing for it to reach. AA71 = Apple, AA72 = Android. Official wording: the mobile device 'has 0 systems stored and no wifi connected (using 3/4G)'.	🟢 Connect your phone to the same WiFi as the wall touchscreen, open your Advantage Air app to pair with the system, then try again away from home. If it still won't connect, call 1300 850 191.

MyPlace touchscreen – AC unit fault passthrough

Where the code shows: Wall touchscreen: Setup screen status window (codes shown with a UNIT ERROR prefix or the AC brand's own lettering).

Tap your code: AC unit error / status code (varies)

Code	What it means	What to do
AC unit error / status code (varies)	The touchscreen is relaying a fault code from the connected air-conditioning unit itself. The code belongs to the AC brand's own fault system, not to Advantage Air. Advantage Air's status-code page confirms the format: anything starting with UNIT ERROR, or any letter combination that isn't AA, is the air conditioner's own code. The CB7 control box pairs with Carrier, Daikin, Fujitsu, LG, Midea, Mitsubishi Electric, Mitsubishi Heavy Industries, Panasonic, Samsung, Toshiba, Hitachi, Haier and Rinnai units, so the code shown follows that brand's numbering.	🟡 Write down the code exactly as shown, try one power-cycle at the outdoor isolator (off, wait at least 5 minutes, back on, then allow about 3 minutes to restart). If the code returns, look it up under your air conditioner's brand or book a service.

Code still showing after a reset? Mention the code and your system type when you book and our office can line up the right technician and likely parts before we arrive.

Book a service or call (02) 4760 0100 (24-hour line, Penrith & Blue Mountains).

ActronAir fault codes for every range

by AmpleJon | Aug 3, 2026

When your ActronAir system stops and shows a code, that code is the system telling you roughly where the problem is. Roughly is the key word. A fault code points in a direction, it rarely names the exact fix. Find your system below, tap your code, and it will take you straight to what it means and what to do.

Aurora (SWB) wall-hung split

Where the code shows: Code on the indoor unit display; operation and timer lamps flash a matching count.

Tap your code: E0 E1 E3 E4 E5 EC F1 F2 F3 F4 F5 P0 P1 P2 P4 CP

Code	What it means	What to do
E0	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM parameter error. Operation lamp flashes once.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch. Operation lamp flashes twice.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The indoor fan isn't running at the speed it should. Indoor fan speed out of control. Operation lamp flashes 4 times.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E4	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit. Operation lamp flashes 5 times.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit. Operation lamp flashes 6 times.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC	The system thinks it is losing refrigerant. Refrigerant leakage detection. Operation lamp flashes 7 times.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit. Timer lamp on, operation lamp flashes twice.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor T5, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed out of control.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P0	The outdoor unit's power module has shut down to protect itself. IPM malfunction or IGBT over-strong current protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection. Can follow grid brownouts or surges.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P2	The compressor got too hot and shut itself down. High temperature protection of compressor top. Applies to SWB52C and SWB70C models only.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P4	The electronics that drive the compressor have reported a fault. Inverter compressor drive error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
CP	The unit has been switched off through its remote on/off connection. Remote On/Off terminal is open circuit. Usually relates to an installer-fitted external switch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.

Serene (WRC / WRE) wall-hung split

Where the code shows: Code on the indoor unit display; operation and timer lamps flash a matching count.

Tap your code: E0 E1 E3 E4 E5 EC F0 F1 F2 F3 F4 F5 P0 P1 P2 P4 CP

Code	What it means	What to do
E0	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM parameter error. Operation lamp flashes once.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The indoor fan isn't running at the speed it should. Indoor fan speed out of control.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E4	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC	The system thinks it is losing refrigerant. Refrigerant leakage detection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
F0	The unit shut down because it was drawing too much current. Overload current protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor T5, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed out of control.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P0	The outdoor unit's power module has shut down to protect itself. IPM malfunction or IGBT over-strong current protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P2	The power module or the compressor got too hot and the unit shut down to protect itself. High temperature protection of IPM module or compressor top.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P4	The electronics that drive the compressor have reported a fault. Inverter compressor drive error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
CP	The unit has been switched off through its remote on/off connection. Remote On/Off terminal is open circuit. 2024 table only; not listed for Serene in 2018.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.

Cascade (URC / CRE) split system, R-410A

Where the code shows: Indoor unit display and lamp flashes; J-codes and duplicates also on the outdoor unit board.

Tap your code: E0 E1 E3 E4 E5 EC EE E8 E9 F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 P0 P1 P2 P3 P4 P6 P7 J0 J1 J2 J3 J4 J5 J6 J8

Code	What it means	What to do
E0	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM malfunction.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch. Also shown on the outdoor board.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The indoor fan isn't running at the speed it should. Indoor fan speed out of control.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E4	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC	The system thinks it is losing refrigerant. Refrigerant leakage detection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EE	The unit can't clear its condensate water properly and the water level alarm has tripped. Water level arm (float/level switch) malfunction.	🟡 Switch the unit off so water can't overflow, and book a service.
E8	The two units of a twin system have lost communication with each other. Master-slave communication error, twin systems only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E9	Another indoor unit on this twin system has a fault. Check the other indoor unit's display for its own code. Twin systems only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F0	The unit shut down because it was drawing too much current. Over-current protection (some units). The outdoor board also uses F0 for overcurrent protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor T5, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM malfunction (some units).	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed malfunction.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
F6	The indoor coil outlet temperature sensor isn't reading properly. T2B sensor, open or short circuit (free-match indoor units).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F7	The cassette's auto-lifting panel and the unit have lost communication. Communication error between auto-lifting panel and slim cassette (source misprints 'sim cassette').	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F8	The cassette's auto-lifting panel has a fault. Slim cassettes with an auto-lifting panel only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F9	The cassette's auto-lifting panel hasn't closed properly. Slim cassettes with an auto-lifting panel only.	🟡 Check nothing is caught in or under the panel, then power-cycle at the isolator. If the code returns, book a service.
P0	The outdoor unit's power module has shut down to protect itself. IPM module malfunction/protection. Same code on indoor display and outdoor board.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The drive's internal DC voltage went too high or too low. DC voltage too high/low protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P2	The compressor got too hot and shut itself down. Top of compressor high temperature protection. Indoor display only.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P3	It's too cold outside for the unit to run safely, so it has protected itself. Low ambient temperature protection (outdoor board wording: ultra-low ambient).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P4	The electronics that drive the compressor have reported a fault. Indoor table: inverter compressor drive protection. Outdoor table: compressor rotor position protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P6	The compressor's supply voltage went outside its safe range. Compressor voltage protection. Indoor display only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P7	A temperature sensor inside the outdoor unit's drive electronics is faulty. Outdoor IGBT sensor faulty.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J0	The indoor coil got too hot and the unit protected itself. Evaporator high temperature protection. Outdoor board display.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
J1	The outdoor coil got too hot and the unit protected itself. Condenser high temperature protection. Outdoor board display.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
J2	The compressor is running much hotter than it should. High discharge temperature protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
J3	A power-conditioning module in the outdoor unit has shut down to protect itself. PFC (power factor correction) module protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J4	Two control chips inside the outdoor unit have stopped talking to each other. Communication error between outdoor main chip and compressor driver chip. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J5	System pressure went too high and the safety cut in. High pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
J6	System pressure went too low and the safety cut in. This can point to low refrigerant. Low pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
J8	The incoming power voltage went outside the unit's safe range. AC power input voltage protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Cascade R-32 (URC / CRC) split system

Where the code shows: Indoor unit display; operation and timer lamps flash a matching count.

Tap your code: EH00 / EH0A EL01 EH03 EH60 EH61 EL0C EH0b EH0E EC53 EC52 EC54 EC56 EC51 EC07 PC00 PC01 PC02 PC04 PC03 EC0D EHbA EH3A EH3b

Code	What it means	What to do
EH00 / EH0A	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM parameter error. Operation lamp flashes once.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EL01	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EH03	The indoor fan isn't running at the speed it should. Indoor fan speed outside normal range (some models).	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
EH60	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH61	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EL0C	The system thinks it is losing refrigerant. Refrigerant leakage detection (some models).	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EH0b	Two control chips inside the indoor unit have stopped talking to each other. Communication error between the two indoor chips.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH0E	The unit can't clear its condensate water properly and the water level alarm has tripped. Water-level alarm malfunction.	🟡 Switch the unit off so water can't overflow, and book a service.
EC53	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC52	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC54	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor TP, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC56	The indoor coil outlet temperature sensor isn't reading properly. T2B sensor, open or short circuit (free-match indoor units).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC51	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EC07	The outdoor fan isn't running at the speed it should. Outdoor fan speed outside normal range (some models).	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
PC00	The outdoor unit's power module has shut down to protect itself. IPM malfunction or IGBT over-strong current protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC01	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC02	The compressor or its power module got too hot and the unit shut down to protect itself. Top-of-compressor or IPM high temperature protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
PC04	The electronics that drive the compressor have reported a fault. Inverter compressor drive error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC03	System pressure went too high or too low and the safety cut in. High or low pressure protection (some models).	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EC0D	The outdoor unit has a fault. Outdoor unit malfunction. Check the outdoor board for its own code.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EHbA	The external fan module and the indoor unit have lost communication. Communication malfunction between external fan module and indoor unit.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EH3A	The external fan module's internal voltage is too low. External fan DC bus voltage too low protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH3b	The external fan module's internal voltage is too high. External fan DC bus voltage too high fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Ultra Slim (URC / LRE) split ducted, R-410A

Where the code shows: Indoor unit display and lamp flashes; J-codes and duplicates also on the outdoor unit board.

Tap your code: E0 E1 E3 E4 E5 EC EE E8 E9 F0 F1 F2 F3 F4 F5 F6 P0 P1 P2 P3 P4 P6 P7 J0 J1 J2 J3 J4 J5 J6 J8

Code	What it means	What to do
E0	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM malfunction.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch. Also shown on the outdoor board.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The indoor fan isn't running at the speed it should. Indoor fan speed out of control.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E4	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC	The system thinks it is losing refrigerant. Refrigerant leakage detection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EE	The unit can't clear its condensate water properly and the water level alarm has tripped. Water level arm (float/level switch) malfunction.	🟡 Switch the unit off so water can't overflow, and book a service.
E8	The two units of a twin system have lost communication with each other. Master-slave communication error, twin systems only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E9	Another indoor unit on this twin system has a fault. Check the other indoor unit's display for its own code. Twin systems only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F0	The unit shut down because it was drawing too much current. Over-current protection (some units). The outdoor board also uses F0 for overcurrent protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor T5, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM malfunction (some units).	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed malfunction.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
F6	The indoor coil outlet temperature sensor isn't reading properly. T2B sensor, open or short circuit (free-match indoor units).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P0	The outdoor unit's power module has shut down to protect itself. IPM module malfunction/protection. Same code on indoor display and outdoor board.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The drive's internal DC voltage went too high or too low. DC voltage too high/low protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P2	The compressor got too hot and shut itself down. Top of compressor high temperature protection. Indoor display only.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P3	It's too cold outside for the unit to run safely, so it has protected itself. Low ambient temperature protection (outdoor board wording: ultra-low ambient).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P4	The electronics that drive the compressor have reported a fault. Indoor table: inverter compressor drive protection. Outdoor table: compressor rotor position protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P6	The compressor's supply voltage went outside its safe range. Compressor voltage protection. Indoor display only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P7	A temperature sensor inside the outdoor unit's drive electronics is faulty. Outdoor IGBT sensor faulty.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J0	The indoor coil got too hot and the unit protected itself. Evaporator high temperature protection. Outdoor board display.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
J1	The outdoor coil got too hot and the unit protected itself. Condenser high temperature protection. Outdoor board display.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
J2	The compressor is running much hotter than it should. High discharge temperature protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
J3	A power-conditioning module in the outdoor unit has shut down to protect itself. PFC (power factor correction) module protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J4	Two control chips inside the outdoor unit have stopped talking to each other. Communication error between outdoor main chip and compressor driver chip. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J5	System pressure went too high and the safety cut in. High pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
J6	System pressure went too low and the safety cut in. This can point to low refrigerant. Low pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
J8	The incoming power voltage went outside the unit's safe range. AC power input voltage protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Ultra Slim R-32 (URC / LRE / LRC) split ducted

Where the code shows: Indoor unit display; separate code set on the outdoor unit board (marked in each row).

Tap your code: EH00 / EH0A EL01 EH03 EH60 EH61 EL0C EH0b EH0E EC53 EC52 EC54 EC56 EC51 EC07 PC00 PC01 PC02 PC04 PC03 EC0D EHbA EH3A EH3b E1 F0 F1 F2 F3 F4 F5 P0 P1 P2 P4 J0 J1 J2 J3 J4 J5 J6 P7 J8 LP

Code	What it means	What to do
EH00 / EH0A	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM parameter error. Operation lamp flashes once.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EL01	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EH03	The indoor fan isn't running at the speed it should. Indoor fan speed outside normal range (some models).	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
EH60	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH61	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EL0C	The system thinks it is losing refrigerant. Refrigerant leakage detection (some models).	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EH0b	Two control chips inside the indoor unit have stopped talking to each other. Communication error between the two indoor chips.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH0E	The unit can't clear its condensate water properly and the water level alarm has tripped. Water-level alarm malfunction.	🟡 Switch the unit off so water can't overflow, and book a service.
EC53	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC52	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC54	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor TP, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC56	The indoor coil outlet temperature sensor isn't reading properly. T2B sensor, open or short circuit (free-match indoor units).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC51	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EC07	The outdoor fan isn't running at the speed it should. Outdoor fan speed outside normal range (some models).	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
PC00	The outdoor unit's power module has shut down to protect itself. IPM malfunction or IGBT over-strong current protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC01	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC02	The compressor or its power module got too hot and the unit shut down to protect itself. Top-of-compressor or IPM high temperature protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
PC04	The electronics that drive the compressor have reported a fault. Inverter compressor drive error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
PC03	System pressure went too high or too low and the safety cut in. High or low pressure protection (some models).	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EC0D	The outdoor unit has a fault. Outdoor unit malfunction. Check the outdoor board for its own code.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EHbA	The external fan module and the indoor unit have lost communication. Communication malfunction between external fan module and indoor unit.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EH3A	The external fan module's internal voltage is too low. External fan DC bus voltage too low protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EH3b	The external fan module's internal voltage is too high. External fan DC bus voltage too high fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E1	The indoor and outdoor units have lost communication with each other. Outdoor board display. Indoor-outdoor communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F0	The outdoor unit shut down because it was drawing too much current. Outdoor overcurrent protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4, open or short circuit. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3, open or short circuit. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor TP, open or short circuit. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor EEPROM malfunction. Outdoor board display.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed out of control. Outdoor board display.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P0	The outdoor unit's power module has shut down to protect itself. IPM module protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P2	The compressor got too hot and shut itself down. Top temperature protection of compressor. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P4	The electronics that drive the compressor have reported a fault. Inverter compressor drive error. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J0	The indoor coil got too hot and the unit protected itself. High temperature protection of evaporator. Outdoor board display.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
J1	The outdoor coil got too hot and the unit protected itself. High temperature protection of condenser. Outdoor board display.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
J2	The compressor is running much hotter than it should. Compressor discharge temperature protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
J3	A power-conditioning module in the outdoor unit has shut down to protect itself. PFC module protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J4	Two boards inside the outdoor unit have stopped talking to each other. Communication malfunction between IPM board and outdoor main board. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J5	System pressure went too high and the safety cut in. High pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
J6	System pressure went too low and the safety cut in. This can point to low refrigerant. Low pressure protection. Outdoor board display.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P7	The drive electronics temperature sensor isn't reading properly. IGBT temperature sensor TH, open or short circuit. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
J8	The incoming power voltage went outside the unit's safe range. AC power input voltage protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
LP	It's too cold outside for the unit to run safely, so it has protected itself. Low ambient temperature protection. Outdoor board display.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Multi-split indoor units (MRE / BRE)

Where the code shows: Indoor unit display; operation and timer lamps flash a matching count. Same letters mean different things on the outdoor unit – check the right list..

Tap your code: CP E0 E1 E3 E4 E5 E7 EE F1 F2 F3 F4 F5 F6 P0 P1 P4 P5

Code	What it means	What to do
CP	The unit has been switched off by a remote switch. Off by remote switch (installer-fitted external control).	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E0	The indoor unit's control board has lost its stored settings. Indoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The indoor fan isn't running at the speed it should. Indoor fan speed malfunction.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E4	The room temperature sensor isn't reading properly. Indoor room temperature sensor T1 malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor coil temperature sensor isn't reading properly. Evaporator coil temperature sensor T2 malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E7	The unit's display panel and its main control board have stopped talking to each other. Communication error between indoor PCB and display PCB.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EE	The unit can't clear its condensate water properly and the water level alarm has tripped. Water-level alarm malfunction. Cassette and ducted indoor types only.	🟡 Switch the unit off so water can't overflow, and book a service.
F1	The outdoor air temperature sensor isn't reading properly. Outdoor ambient temperature sensor T4 malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The outdoor coil temperature sensor isn't reading properly. Condenser coil temperature sensor T3 malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The compressor outlet temperature sensor isn't reading properly. Compressor discharge temperature sensor T5 malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F5	The outdoor fan isn't running at the speed it should. Outdoor fan speed malfunction.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
F6	The indoor coil outlet pipe sensor isn't reading properly. Indoor coil outlet pipe sensor malfunction; the sensor sits at the outdoor unit's low pressure valve.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P0	The outdoor unit's power module has shut down to protect itself. Inverter module (IPM) malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P4	The electronics that drive the compressor have reported a fault. Compressor drive malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P5	Two indoor units are asking for opposite modes (one heating, one cooling), which a multi system can't do at once. Indoor unit mode conflict.	🟢 Set every indoor unit to the same mode (all cooling or all heating) at the controllers. If the code stays after that, power-cycle at the isolator, then book a service if it returns.

Multi-split outdoor unit (MRC)

Where the code shows: Outdoor unit LED display. Same letters mean different things on the indoor units – check the right list..

Tap your code: E0 E2 E3 E4 E5 E6 E8 F1 F2 F3 F4 F5 P1 P2 P3 P4 P5 P6

Code	What it means	What to do
E0	The outdoor unit's control board has lost its stored settings. Outdoor unit EEPROM parameter error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E2	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication malfunction. Per the 2017 troubleshooting guide this code does not self-clear.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	Two boards inside the outdoor unit have stopped talking to each other. Communication malfunction between IPM board and outdoor main control board.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E4	One of the outdoor unit's temperature sensors isn't reading properly. Covers coil sensor T3, ambient sensor T4, compressor discharge sensor T5 and indoor coil outlet pipe sensor T2B.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The incoming power voltage went too high or too low. Over-voltage or under-voltage protection. Often follows supply problems; the unit restarts once power is normal.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E6	A power-conditioning module in the outdoor unit has shut down to protect itself. PFC module protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E8	The outdoor fan isn't running at the speed it should. Outdoor fan speed malfunction.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
F1	The coil outlet sensor for indoor unit A isn't reading properly. Indoor unit A coil outlet temperature sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F2	The coil outlet sensor for indoor unit B isn't reading properly. Indoor unit B coil outlet temperature sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F3	The coil outlet sensor for indoor unit C isn't reading properly. Indoor unit C coil outlet temperature sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F4	The coil outlet sensor for indoor unit D isn't reading properly. Indoor unit D coil outlet temperature sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F5	The coil outlet sensor for indoor unit E isn't reading properly. Indoor unit E coil outlet temperature sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P1	System pressure went too high and the safety cut in. High pressure protection. MRC-100AS-4, MRC-110AS-5 and MRC-135AS-5 only.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
P2	System pressure went too low and the safety cut in. This can point to low refrigerant. Low pressure protection. MRC-100AS-4, MRC-110AS-5 and MRC-135AS-5 only.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P3	The outdoor unit shut down because it was drawing too much current. Current overload protection.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P4	The compressor is running much hotter than it should. This can point to low refrigerant. Compressor discharge temperature protection. 2017 guide: trips when discharge exceeds 115 degrees C; refrigerant leakage is a listed cause.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P5	The outdoor coil got too hot and the unit protected itself. Condenser high temperature protection. 2017 guide: trips above 65 degrees C pipe temperature; dirty coil or blocked airflow are listed causes.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P6	The outdoor unit's power module has shut down to protect itself. Inverter module (IPM) protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

WC-02 wired wall controller

Where the code shows: WC-02 controller screen.

Tap your code: E0 E1 E2 E3 E4 E6 E7 E8 E9 EA EB EC ED EE EF F0 F1 P0 P1 P2 P3 P4 P5 P6 P7 P8 PF

Code	What it means	What to do
E0	There's a problem with the order or presence of the incoming power phases. Phase sequence error or phase malfunction. Three-phase supply issue; needs an electrician or technician.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E1	The indoor and outdoor units have lost communication with each other. Indoor-outdoor communication malfunction.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E2	The room temperature sensor isn't reading properly. T1 sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E3	The indoor coil temperature sensor isn't reading properly. T2A sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E4	The indoor coil outlet temperature sensor isn't reading properly. T2B sensor malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E6	The controller's electrical timing check has failed. Zero check (zero-cross detection) malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E7	The indoor unit's control board has lost its stored settings. Indoor EEPROM malfunction (source misprints 'EERROM').	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E8	The fan controller isn't responding properly. Fan controller out of control.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E9	The main control board and the display have stopped talking to each other. Communication malfunction between main PCB and display board.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
EA	The compressor is overloaded. Compressor overload; source notes '(4 times)'.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
EB	The outdoor unit's power module has a fault. IPM module malfunction (source misprints 'IPM mould').	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EC	The air-cleaning function has a fault. Air clean malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
ED	The outdoor unit has shut down on one of its protections. Outdoor malfunction protection. Check the outdoor unit for its own code.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
EE	The condensate tray is full and the unit has stopped to avoid overflow. Full-water malfunction.	🟡 Switch the unit off so water can't overflow, and book a service.
EF	The system has a fault it can't name on this display. Other fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
F0	The wired controller and the indoor unit have lost communication. Communication error between wired controller and indoor unit. 2024 edition only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
F1	The cassette's drop-down fascia panel hasn't closed properly. Elevating fascia panel not closed. 2024 edition only.	🟡 Check nothing is caught in or under the panel, then power-cycle at the isolator. If the code returns, book a service.
P0	The indoor coil went outside its safe temperature range and the unit protected itself. Evaporator temperature protection. A dirty filter or blocked vents are common causes.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
P1	The unit is running its defrost or anti-cold-air mode. This is normal, not a fault. Anti-cold-air or defrost mode indicator.	🟢 Nothing to do. This is normal operation, not a fault. If it never clears, power-cycle at the isolator and book a service if it persists.
P2	The outdoor coil got too hot and the unit protected itself. Condenser temperature protection.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
P3	The compressor got too hot and shut itself down. Compressor temperature protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P4	The compressor's outlet pipe got too hot and the unit protected itself. Discharge pipe temperature protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P5	System pressure went too high and the safety cut in. Discharge high pressure protection.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
P6	System pressure went too low and the safety cut in. This can point to low refrigerant. Discharge low pressure protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
P7	The incoming power voltage went too high. Over-voltage protection.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
P8	The compressor is overloaded. Compressor overload protection.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
PF	There's a fault elsewhere in the system. Other fault; check the indoor or outdoor unit for its own code. (2018 edition lists P9-PE as unused reserve codes.)	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Classic (SRE* / SRA / SRG) split ducted

Where the code shows: LM7 or LM24 wall controller; single-digit codes on the outdoor CPU LED. *SRE applies to SRE091C/SRG091E only..

Tap your code: COOL + LOW flashing HEAT + HIGH flashing E6 E7 E9 E5 E3 E4

Code	What it means	What to do
COOL + LOW flashing	The indoor coil is getting too cold, so the unit has dropped to low capacity to stop ice forming. Anti-freeze protection mode (low capacity mode), flashing for 30 seconds on the LM7/LM24 wall controller. Dirty filters or closed vents are the classic cause.	🟢 Check the return-air filter is clean and all vents and grilles are open, then power-cycle at the isolator. If it keeps happening, book a service.
HEAT + HIGH flashing	The unit is getting too hot in heating and has protected itself. Overheat safety protection, flashing for 30 seconds on the wall controller.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E6	The compressor is running much hotter than it should. The doc links this to being low on refrigerant. Fault: discharge high temperature (low on refrigerant). Outdoor CPU shows 6.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E7	The outdoor coil sensor isn't reading properly. Outdoor coil sensor open or short circuit. Outdoor CPU shows 7.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E9	A pressure safety has tripped, or there's a power phase problem. High or low pressure / phase error. Outdoor CPU shows 9.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E5	The indoor and outdoor units have lost communication with each other. Communication error between outdoor and indoor. Wall controller only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The room temperature sensor isn't reading properly. Room sensor(s) open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E4	The indoor coil sensor isn't reading properly. Indoor coil-in sensor open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Classic 2 (CRA / CCA / EVA / EAA / EFA) split ducted

Where the code shows: LR7-1 wall controller and outdoor CPU display.

Tap your code: COOL + LOW flashing HEAT + HIGH flashing E01 E03 E04 E07 E09 E11 E51 E52 E55 E56

Code	What it means	What to do
COOL + LOW flashing	The indoor coil is getting too cold, so the unit has protected itself against icing up. Anti-freeze protection mode, flashing 30 seconds on the LR7-1 wall controller.	🟢 Check the return-air filter is clean and all vents and grilles are open, then power-cycle at the isolator. If it keeps happening, book a service.
HEAT + HIGH flashing	The unit is getting too hot in heating and has protected itself. Overheat protection mode, flashing 30 seconds on the wall controller.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E01	The indoor fan isn't running at the speed the system asked for. Indoor fan RPM feedback error.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E03	The room temperature sensor isn't reading properly. Room temperature error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil sensor isn't reading properly. Indoor coil sensor error. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E07	The outdoor coil sensor isn't reading properly. Outdoor coil sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP switch tripped. May not show on the wall control until it has happened several times.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E11	The high-pressure safety switch has tripped. HP switch tripped. May not show on the wall control until it has happened several times.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E51	The indoor and outdoor units have lost communication with each other. IDU-ODU communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E52	The indoor unit and the wall controller have lost communication. IDU-wall controller communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E55	The connection to the building management system has dropped out. BMS-ODU communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E56	The system can't find a master wall controller. No master wall controller detected. Can appear after power interruptions; if it stays, it needs a technician.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.

ESP Digital (SRD / SRV) split ducted

Where the code shows: LM7 or LM24 wall controller; single-digit codes on the outdoor CPU LED.

Tap your code: LOW flashing E6 E7 E8 E9 E5 E3 E4 E2

Code	What it means	What to do
LOW flashing	The unit has dropped to low capacity to protect itself against overheating or icing up. Overheat or anti-freeze protection mode (low capacity mode), LOW speed flashing 30 seconds on the wall controller. Outdoor CPU shows 4.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E6	The compressor is running much hotter than it should. The doc links this to being low on refrigerant. Fault: discharge high temperature (low on refrigerant). Outdoor CPU shows 6.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E7	The outdoor coil sensor isn't reading properly. Outdoor coil sensor open or short circuit. Outdoor CPU shows 7.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E8	The outdoor discharge sensor isn't reading properly. Outdoor discharge sensor open or short circuit. Outdoor CPU shows 8.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E9	A pressure safety has tripped, or there's a power phase problem. High or low pressure / phase error. Three-phase models only. Outdoor CPU shows 9.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E5	The indoor and outdoor units have lost communication with each other. Communication error between outdoor and indoor. Wall controller only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E3	The room temperature sensor isn't reading properly. Room sensor(s) open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E4	The indoor coil inlet sensor isn't reading properly. Indoor coil-in sensor open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E2	The indoor coil outlet sensor isn't reading properly. Indoor coil-out sensor open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

ESP Platinum (CRV / ERV / ARV / FRV / ERM) split ducted

Where the code shows: LM7/LM24 wall controller and outdoor CPU 7-segment display; a subset shows on the LM-ZC zone controller.

Tap your code: E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E14 E15 E17 E18 E19 E22 E23 E25 E26 E27 E28 E29 E30 E31 E32 / E33 E34 E35 E36 E37 E38 E39 E40 E41 E99

Code	What it means	What to do
E3	The room temperature sensor isn't reading properly. Room sensor error, open or short circuit. Wall and zone controllers.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E4	The indoor coil inlet sensor isn't reading properly. Indoor coil inlet sensor error, open or short circuit. Wall controller only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E5	The indoor and outdoor units have lost communication with each other. IDU-ODU communication error. Outdoor CPU shows E05.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E6	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature; trips when discharge exceeds 138 degrees C.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E7	The outdoor coil sensor isn't reading properly. Outdoor coil sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E8	The outdoor discharge sensor isn't reading properly. Outdoor discharge sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E9	The low-pressure safety switch has tripped. This often points to low refrigerant. LP tripped.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP tripped.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E14	Pressure on the outdoor coil side is unusually low. Condenser pressure low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. VSD communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E17	One of the outdoor unit's peripheral devices has a fault. Peripherals error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E18	The suction temperature sensor isn't reading properly. In EEV module, suction temp sensor is open.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E19	The suction temperature sensor isn't reading properly. In EEV module, suction temp sensor is shorted.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor has failed, so the unit is running in a limited safe mode. Ambient sensor failure (open/short circuit), safe mode.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E23	A control board for the refrigerant valve has lost communication, so the unit is running in a limited safe mode. EEV board communication failure, safe mode.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E25	The outdoor temperature reading isn't updating. Ambient temperature not updated (status).	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E26	The inverter drive has detected too much current. VSD over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected voltage that is too high. VSD over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The inverter drive is running too hot. VSD temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. Low supply voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. VSD trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E31	The inverter drive has an internal fault. VSD internal error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E32 / E33	A pressure safety tripped based on the drive's pressure sensors. Envelope protection: HP/LP trip error via VSD pressure sensors.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E34	The unit has wound itself back because the inverter drive is running hot. Derating: high VSD temperature.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E35	The unit has wound itself back because suction pressure is low. Derating: low suction pressure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E36	The unit has wound itself back because condenser pressure is low. Derating: low condenser pressure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E37	The unit has wound itself back because condenser pressure is high. Derating: high condenser pressure. Note: the wall controller also briefly shows E37 as a status during indoor coil pre-heat after defrost, which is normal.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E38	The unit has wound itself back to its output power limit. Derating: output power limit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E39	A defrost cycle took too long and timed out. Defrosting timed out.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E40	The inverter drive is restarting too often. VSD restarting too frequently.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. VSD DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E99	The system is operating outside its safe pressure/temperature envelope. Envelope protection. Listed in the Platinum service manual (Sec. 15); not shown in the 2024 Platinum table but present in the QUE table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

ESP QUE Platinum (CRQ / ERQ / ARV / FRQ) split ducted

Where the code shows: QT-1000 master controller (status bar and Tech Menu) and outdoor CPU display.

Tap your code: E03 E04 E05 E06 E07 E08 E09 E10 E11 E12 E13 E14 E15 E17 E18 / E19 E22 E23 E25 E26 E27 E28 E29 E30 E31 E32 / E33 E34 E35 / E36 / E37 E38 E39 E40 E41 E42 E43 E44 E45 E47 E50 E51 E52 E53 E60 E62 E63 E66 E67 E69 E70 E71 E72 E74 E75 E76 E77 E78 E80 E81 E82 E83 E84 E85 E86 E87 E88 E89 E90 E91 E92 E99

Code	What it means	What to do
E03	The room temperature sensor isn't reading properly. Room sensor error, open or short circuit. Single-phase: shown in controller Tech Menu as E3.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil sensor isn't reading properly. Single-phase: indoor coil inlet sensor (Tech Menu E4). Three-phase table lists indoor coil out sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E05	The indoor and outdoor units have lost communication with each other. Shown as E05 on the outdoor CPU and as E51 in the controller Tech Menu.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E06	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature; trips when discharge exceeds 138 degrees C. Tech Menu E6.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E07	The outdoor coil sensor isn't reading properly. Outdoor coil sensor error, open or short circuit. Tech Menu E7.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E08	The outdoor discharge sensor isn't reading properly. Outdoor discharge sensor error, open or short circuit. Tech Menu E8.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP tripped. Tech Menu E9.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP tripped.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E13	The outdoor unit's inverter drive has reported a fault. Three-phase table: VSD HSP connector (jumper pin missing) / other drive errors.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E14	Pressure on the outdoor coil side is unusually low. Condenser pressure low. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. VSD communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E17	One of the outdoor unit's peripheral devices has a fault. Peripherals error. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E18 / E19	The suction temperature sensor isn't reading properly. Single-phase: in EEV module, suction temp sensor open (E18) or shorted (E19). Three-phase lists only E18, abnormal reading value.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor has failed; single-phase units drop to a limited safe mode. Ambient sensor failure, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E23	A control board for the refrigerant valve has lost communication, so the unit is running in a limited safe mode. EEV board communication failure, safe mode. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E25	The outdoor temperature reading isn't updating. Ambient temperature not updated (status). Single-phase table.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E26	The inverter drive has detected too much current. Over current (three-phase table: alarm-over current).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected voltage that is too high. Over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The inverter drive is running too hot. VSD/drive temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. Low supply voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. Trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E31	The inverter drive has an internal fault. VSD internal error. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E32 / E33	A pressure safety tripped based on the drive's pressure sensors. Envelope protection: HP/LP trip error via VSD pressure sensors. Single-phase table.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E34	The unit has wound itself back because the inverter drive is running hot. Derating: high VSD temperature. Single-phase table.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E35 / E36 / E37	The unit has wound itself back because system pressure is outside its comfort zone. Derating: low suction (E35), low condenser (E36) or high condenser (E37) pressure. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E38	The unit has wound itself back to its output power limit. Derating: output power limit. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E39	A defrost cycle took too long and timed out. Defrosting timed out. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E40	The inverter drive is restarting too often. VSD restarting too frequently. Single-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E42	The system is operating outside its safe pressure/temperature envelope. Envelope protection error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E43	The system is operating outside its safe pressure/temperature envelope. Envelope protection error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E44	The system is operating outside its safe pressure/temperature envelope. Envelope protection error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E45	The system is operating outside its safe pressure/temperature envelope. Envelope protection error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E47	The compressor hit its torque limit. Compressor torque limit error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E50	The outdoor unit's control board has a configuration problem. Outdoor board configuration error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E51	The indoor and outdoor units have lost communication with each other. IDU-ODU communication error. Three-phase table; on single-phase the outdoor CPU shows E05 for this.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E52	The indoor unit and the master controller have lost communication. Shown in the controller Tech Menu.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E53	The indoor unit and its zone module have lost communication. IDU VAV/VAQ zone module communication error. Shown in the controller Tech Menu.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E60	The drive measured too much current going to the compressor. VSD compressor phase over current. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E62	The drive's internal DC voltage went too high. VSD DC bus over voltage. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E63	The drive's internal DC voltage went too low. VSD DC bus under voltage. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E66	The incoming power phases are unbalanced, or a phase has dropped out. VSD AC voltage imbalance / AC input loss of phase. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E67	The drive's power electronics reported an internal switching fault. VSD inverter de-saturation. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E69	Part of the drive's power electronics is overheating. VSD PFC-IGBT over temperature. Three-phase table.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E70	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E71	The compressor motor's temperature sensor is faulty. Motor thermistor fault. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E72	A startup relay inside the drive isn't closing properly. VSD precharge relay open. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E74	The drive measured too much current going to the compressor. VSD compressor phase over current. Three-phase table lists E74 as compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E75	The drive repeatedly had to wind back compressor current and eventually shut down. VSD compressor phase current foldback timeout. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E76	The drive repeatedly had to wind back for module temperature and eventually shut down. VSD power module temperature foldback timeout. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E77	The drive repeatedly had to wind back input current and eventually shut down. VSD AC input current foldback timeout. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E78	The drive's automatic configuration handshake timed out. VSD auto config communication timeout. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E80	The compressor motor is running too hot. VSD motor temperature high. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E81	A circuit board in the drive is running too hot. VSD board temperature high. Three-phase table.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E82	The drive's power module is running too hot. VSD power module temperature high. Three-phase table.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E83	Part of the drive's power electronics is running too hot. VSD PFC-IGBT temperature high. Three-phase table.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E84	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between DSP and PFC. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E85	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between comms processor and DSP. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E86	Current to the compressor is unbalanced across its phases. VSD compressor phase current imbalance. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E87	Current inside the drive's power-correction circuit is unbalanced. VSD 3-phase PFC current imbalance. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E88	The drive's electronics or memory have an internal fault. VSD micro-electronic or EEPROM error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E89	The compressor motor ran faster than allowed. VSD motor over speed. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E90	The drive doesn't recognise the compressor it's connected to. VSD compressor model configuration error. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E91	Temperatures inside the drive's inverter section are unbalanced. VSD inverter temperature imbalance. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E92	Temperatures inside the drive's power-correction section are unbalanced. VSD PFC temperature imbalance. Three-phase table.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E99	The system is operating outside its safe pressure/temperature envelope. Envelope protection. Shown in the controller Tech Menu.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Advance (CRV / EVV / EAA / EFV) split ducted, R-410A Uno and R-32 Uno Pro boards

Where the code shows: NEO or LR7-1/LC7-2 wall controller and outdoor unit CPU (same code on all three).

Tap your code: E01 E03 E04 E06 E07 E08 E09 E10 E11 E12 E13 E15 E18 E22 E26 E27 E28 E29 E30 E41 E42 E43 E44 E45 E47 E50 E51 E52 E55 E56 E60 E61 E62 E63 E64 E65 E66 E67 E68 E69 E70 E71 E72 E73 E74 E75 E76 E77 E78 E79 E80 E81 E82 E83 E84 E85 E86 E87 E88 E89 E90 E91 E92 E93 E94 E95 E96 E97 E98 E99 E100 E101 E102 E103 E104

Code	What it means	What to do
E01	The indoor fan isn't running at the speed the system asked for. Indoor fan RPM feedback error.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E03	The room temperature sensor isn't reading properly. Indoor room temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil's inlet temperature sensor isn't reading properly. Indoor coil-in temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E06	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature. Trips when discharge temperature exceeds 120 degrees C.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E07	The outdoor coil's temperature sensor isn't reading properly. Outdoor coil temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E08	The compressor outlet temperature sensor isn't reading properly. Discharge temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP switch tripped.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP switch tripped. Blocked outdoor airflow is one common cause.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E13	The outdoor unit's inverter drive has reported a fault. Other drive errors. On Advance R-410A (Uno board) E13 can also mean the VSD HSP connector jumper pin is missing.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. ODU-VSD communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E18	The suction line temperature sensor isn't reading properly. Suction temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor isn't reading properly. Ambient temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E26	The inverter drive has detected too much incoming current. VSD supply/input over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected incoming voltage that is too high. VSD supply/input over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The inverter drive is running too hot. VSD temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. VSD low supply voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. VSD trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. VSD DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E42	The system is running with abnormally low suction pressure. This can point to low refrigerant. Envelope protection error: extreme low evaporating pressure.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E43	The compressor is working outside its safe range (compression ratio too high). Envelope protection error: high compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E44	Pressure on the outdoor coil side is too high for safe operation. Envelope protection error: high condensing pressure.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E45	The compressor is working outside its safe range (compression ratio too low). Envelope protection error: low compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E47	The compressor hit its torque limit. Compressor torque limit error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E50	The outdoor unit's control board has a configuration problem. Outdoor board configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E51	The indoor and outdoor units have lost communication with each other. Outdoor-indoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E52	The indoor unit and the wall controller have lost communication. Indoor unit to wall controller communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E55	The connection to the building management system has dropped out. BMS to outdoor unit communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E56	The system can't find a master wall controller. No master wall controller detected. Can appear after power interruptions; if it stays, it needs a technician.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E60	The drive measured too much current going to the compressor. VSD compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E61	The drive has lost one of the compressor's electrical phases. VSD compressor loss of phase.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E62	The drive's internal DC voltage went too high. VSD DC bus over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E63	The drive's internal DC voltage went too low. VSD DC bus under voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E64	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position. Listed as VSD compressor loss of rotor.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E65	A current sensor inside the drive (phase U) is faulty. VSD compressor U phase current sensor fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E66	The incoming power phases are unbalanced, or a phase has dropped out. VSD AC voltage imbalance / AC input loss of phase. Advance R-410A (Uno board) only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E67	The drive's power electronics reported an internal switching fault. VSD inverter de-saturation. Advance R-410A (Uno board) only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E68	A current sensor inside the drive (phase V) is faulty. VSD compressor V phase current sensor fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E69	Part of the drive's power electronics is overheating. VSD PFC-IGBT over temperature.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E70	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E71	The compressor motor's temperature sensor is faulty. VSD motor temperature sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E72	A startup relay inside the drive isn't closing properly. VSD precharge relay open.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E73	A current sensor inside the drive (phase W) is faulty. VSD compressor W phase current sensor fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E74	The drive's power electronics measured too much current. VSD IGBT over current. Source adds: choke wiring or failure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E75	The drive repeatedly had to wind back compressor current and eventually shut down. VSD compressor phase current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E76	The drive repeatedly had to wind back for module temperature and eventually shut down. VSD power module temperature foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E77	The drive repeatedly had to wind back input current and eventually shut down. VSD AC input current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E78	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E79	The drive's power module reported a hardware over-current. VSD IPM desat protection / compressor hardware over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E80	The compressor motor is running too hot. VSD motor temperature high.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E81	A circuit board in the drive is running too hot. VSD board temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E82	The drive's power module is running too hot. VSD power module temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E83	Part of the drive's power electronics is running too hot. VSD PFC-IGBT temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E84	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between DSP and PFC.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E85	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between comms processor and DSP.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E86	Current to the compressor is unbalanced across its phases. VSD compressor phase current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E87	Current inside the drive's power-correction circuit is unbalanced. VSD 3-phase PFC current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E88	The drive's electronics or memory have an internal fault. VSD micro-electronic or EEPROM error. Advance R-32 (Uno Pro board) only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E89	The compressor motor ran faster than allowed. VSD motor over speed.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E90	The drive doesn't recognise the compressor it's connected to. VSD compressor model configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E91	Temperatures inside the drive's inverter section are unbalanced. VSD inverter temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E92	Temperatures inside the drive's power-correction section are unbalanced. VSD PFC temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E93	The compressor motor is reading abnormally cold. VSD motor temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E94	A circuit board in the drive is reading abnormally cold. VSD board temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E95	The drive's power module is reading abnormally cold, or its sensor is faulty. VSD power module temperature low, or sensor open/short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E96	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low. Listed as VSD PFC-IGBT temp low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E97	An internal measurement circuit in the drive has failed. VSD comms ADC failure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E98	A current-measuring circuit in the drive is faulty. VSD PFC / input current sensor fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E99	The compressor is overloaded. VSD compressor overload.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E100	The drive's power-correction circuit measured too much current (hardware trip). VSD PFC hardware over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E101	The drive's power-correction circuit measured too much current (software trip). VSD PFC software over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E102	The drive's power-correction circuit voltage went too high. VSD PFC over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E103	The drive's power module is reading abnormally cold, or its sensor circuit is open. VSD power module temperature low or sensor open fault. Advance R-32 (Uno Pro board) only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E104	The drive shut down after hitting its fault limit too many times. VSD fault limit lockout. Advance R-32 (Uno Pro board) only.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Aires (CRS / EVA) split ducted

Where the code shows: NEO or LR7-1/LC7-2 wall controller and outdoor unit CPU (same code on all three).

Tap your code: E01 E03 E04 E06 E07 E08 E09 E10 E11 E12 E13 E15 E18 E22 E26 E27 E28 E29 E30 E41 E42 E43 E44 E45 E47 E50 E51 E52 E55 E56 E60 E61 E62 E63 E65 E69 E70 E71 E72 E73 E74 E75 E76 E77 E78 E79 E80 E81 E82 E83 E84 E85 E88 E90 E91 E92 E93 E94 E95 E96 E97 E98 E99 E100 E101 E102 E103 E104

Code	What it means	What to do
E01	The indoor fan isn't running at the speed the system asked for. Indoor fan RPM feedback error.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E03	The room temperature sensor isn't reading properly. Indoor room temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil's inlet temperature sensor isn't reading properly. Indoor coil-in temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E06	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature. Trips when discharge temperature exceeds 138 degrees C.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E07	The outdoor coil's temperature sensor isn't reading properly. Outdoor coil temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E08	The compressor outlet temperature sensor isn't reading properly. Discharge temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP switch tripped.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP switch tripped. Blocked outdoor airflow is one common cause.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E13	The outdoor unit's inverter drive has reported a fault. Other drive errors.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. ODU-VSD communication error. Listed as VSD-ODU Modbus communication lost.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E18	The suction line temperature sensor isn't reading properly. Suction temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor isn't reading properly. Ambient temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E26	The inverter drive has detected too much incoming current. VSD supply/input over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected incoming voltage that is too high. VSD supply/input over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The drive's power module is running too hot. VSD power module temperature high. Listed as VSD power module over temp.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. VSD low supply voltage. Listed as VSD input under voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. VSD trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. VSD DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E42	The system is running with abnormally low suction pressure. This can point to low refrigerant. Envelope protection error: extreme low evaporating pressure.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E43	The compressor is working outside its safe range (compression ratio too high). Envelope protection error: high compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E44	Pressure on the outdoor coil side is too high for safe operation. Envelope protection error: high condensing pressure.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E45	The compressor is working outside its safe range (compression ratio too low). Envelope protection error: low compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E47	The compressor hit its torque limit. Compressor torque limit error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E50	The outdoor unit's control board has a configuration problem. Outdoor board configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E51	The indoor and outdoor units have lost communication with each other. Outdoor-indoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E52	The indoor unit and the wall controller have lost communication. Indoor unit to wall controller communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E55	The connection to the building management system has dropped out. BMS to outdoor unit communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E56	The system can't find a master wall controller. No master wall controller detected. Can appear after power interruptions; if it stays, it needs a technician.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E60	The drive measured too much current going to the compressor. VSD compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E61	The drive has lost one of the compressor's electrical phases. VSD compressor loss of phase. Listed as VSD compressor loss of output phase.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E62	The drive's internal DC voltage went too high. VSD DC bus over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E63	The drive's internal DC voltage went too low. VSD DC bus under voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E65	The drive has lost one of the compressor's electrical phases. VSD compressor loss of phase. Listed as compressor phase loss fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E69	Part of the drive's power electronics is overheating. VSD PFC-IGBT over temperature.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E70	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E71	The compressor motor's temperature sensor is faulty. VSD motor temperature sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E72	A startup relay inside the drive isn't closing properly. VSD precharge relay open.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E73	A current sensor inside the drive (phase W) is faulty. VSD compressor W phase current sensor fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E74	The drive's power electronics measured too much current. VSD IGBT over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E75	The drive repeatedly had to wind back compressor current and eventually shut down. VSD compressor phase current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E76	The drive repeatedly had to wind back for module temperature and eventually shut down. VSD power module temperature foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E77	The drive repeatedly had to wind back input current and eventually shut down. VSD AC input current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E78	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E79	The drive's power module reported a hardware over-current. VSD IPM desat protection / compressor hardware over current. Listed as VSD IPM modular over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E80	The compressor motor is running too hot. VSD motor temperature high.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E81	A circuit board in the drive is running too hot. VSD board temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E82	The drive's power module is running too hot. VSD power module temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E83	Part of the drive's power electronics is running too hot. VSD PFC-IGBT temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E84	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between DSP and PFC.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E85	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between comms processor and DSP.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E88	The drive's electronics or memory have an internal fault. VSD micro-electronic or EEPROM error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E90	The drive doesn't recognise the compressor it's connected to. VSD compressor model configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E91	Temperatures inside the drive's inverter section are unbalanced. VSD inverter temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E92	Temperatures inside the drive's power-correction section are unbalanced. VSD PFC temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E93	The compressor motor is reading abnormally cold. VSD motor temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E94	A circuit board in the drive is reading abnormally cold. VSD board temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E95	The drive's power module is reading abnormally cold, or its sensor is faulty. VSD power module temperature low, or sensor open/short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E96	The temperature-sensing circuit for the drive's power-correction module is faulty. VSD PFC module temperature sensing circuit malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E97	A control chip in the drive keeps resetting. VSD IC reset malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E98	A current-sensing circuit in the drive is faulty. VSD current sensing circuit malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E99	The drive reported an unspecified internal fault. VSD other malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E100	The drive's charging circuit is faulty. VSD charging circuit malfunction.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E101	The drive's power-correction circuit measured too much current (software trip). VSD PFC software over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E102	The drive's power-correction circuit voltage went too high. VSD PFC over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E103	The drive's power module is reading abnormally cold, or its sensor circuit is open. VSD power module temperature low or sensor open fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E104	The drive shut down after hitting its fault limit too many times. VSD fault limit lockout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Commercial Split (SCA / SCG) and Package (PCA / PCG)

Where the code shows: C7 wall controller; single-digit codes on the outdoor CPU LED.

Tap your code: E7 E9 E5

Code	What it means	What to do
E7	The outdoor coil sensor isn't reading properly. Open circuit (outdoor CPU shows 7) or short circuit (outdoor CPU shows 8).	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E9	A pressure safety has tripped. High or low pressure fault. Outdoor CPU shows 9.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E5	The indoor and outdoor units have lost communication with each other. Communication error between outdoor and indoor. C7 wall controller only.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.

Variable Commercial (PRV) package unit

Where the code shows: NEO or LR7-1/LC7-2 wall controller and outdoor unit CPU.

Tap your code: E01 E03 E04 E06 E07 E08 E09 E10 E11 E12 E13 E15 E18 E22 E26 E27 E28 E29 E30 E41 E42 E43 E44 E45 E47 E50 E51 E52 E55 E56 E60 E62 E63 E69 E70 E71 E72 E74 E75 E76 E77 E78 E80 E81 E82 E83 E84 E85 E86 E87 E88 E89 E90 E91 E92 E93 E94 E95 E96 E97 E103 E104

Code	What it means	What to do
E01	The indoor fan isn't running at the speed the system asked for. Indoor fan RPM feedback error.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E03	The room temperature sensor isn't reading properly. Indoor room temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil's inlet temperature sensor isn't reading properly. Indoor coil-in temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E06	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature. Trips when discharge temperature exceeds 120 degrees C.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E07	The outdoor coil's temperature sensor isn't reading properly. Outdoor coil temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E08	The compressor outlet temperature sensor isn't reading properly. Discharge temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP switch tripped.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP switch tripped. Blocked outdoor airflow is one common cause.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E13	The outdoor unit's inverter drive has reported a fault. Other drive errors.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. ODU-VSD communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E18	The suction line temperature sensor isn't reading properly. Suction temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor isn't reading properly. Ambient temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E26	The inverter drive has detected too much incoming current. VSD supply/input over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected incoming voltage that is too high. VSD supply/input over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The inverter drive is running too hot. VSD temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. VSD low supply voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. VSD trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. VSD DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E42	The system is running with abnormally low suction pressure. This can point to low refrigerant. Envelope protection error: extreme low evaporating pressure.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E43	The compressor is working outside its safe range (compression ratio too high). Envelope protection error: high compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E44	Pressure on the outdoor coil side is too high for safe operation. Envelope protection error: high condensing pressure.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E45	The compressor is working outside its safe range (compression ratio too low). Envelope protection error: low compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E47	The compressor hit its torque limit. Compressor torque limit error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E50	The outdoor unit's control board has a configuration problem. Outdoor board configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E51	The indoor and outdoor units have lost communication with each other. Outdoor-indoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E52	The indoor unit and the wall controller have lost communication. Indoor unit to wall controller communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E55	The connection to the building management system has dropped out. BMS to outdoor unit communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E56	The system can't find a master wall controller. No master wall controller detected. Can appear after power interruptions; if it stays, it needs a technician.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E60	The drive measured too much current going to the compressor. VSD compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E62	The drive's internal DC voltage went too high. VSD DC bus over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E63	The drive's internal DC voltage went too low. VSD DC bus under voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E69	Part of the drive's power electronics is overheating. VSD PFC-IGBT over temperature.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E70	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E71	The compressor motor's temperature sensor is faulty. VSD motor temperature sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E72	A startup relay inside the drive isn't closing properly. VSD precharge relay open.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E74	The drive's power electronics measured too much current. VSD IGBT over current. Source adds: choke wiring or failure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E75	The drive repeatedly had to wind back compressor current and eventually shut down. VSD compressor phase current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E76	The drive repeatedly had to wind back for module temperature and eventually shut down. VSD power module temperature foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E77	The drive repeatedly had to wind back input current and eventually shut down. VSD AC input current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E78	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E80	The compressor motor is running too hot. VSD motor temperature high.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E81	A circuit board in the drive is running too hot. VSD board temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E82	The drive's power module is running too hot. VSD power module temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E83	Part of the drive's power electronics is running too hot. VSD PFC-IGBT temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E84	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between DSP and PFC.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E85	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between comms processor and DSP.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E86	Current to the compressor is unbalanced across its phases. VSD compressor phase current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E87	Current inside the drive's power-correction circuit is unbalanced. VSD 3-phase PFC current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E88	The drive's electronics or memory have an internal fault. VSD micro-electronic or EEPROM error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E89	The compressor motor ran faster than allowed. VSD motor over speed.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E90	The drive doesn't recognise the compressor it's connected to. VSD compressor model configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E91	Temperatures inside the drive's inverter section are unbalanced. VSD inverter temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E92	Temperatures inside the drive's power-correction section are unbalanced. VSD PFC temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E93	The compressor motor is reading abnormally cold. VSD motor temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E94	A circuit board in the drive is reading abnormally cold. VSD board temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E95	The drive's power module is reading abnormally cold, or its sensor is faulty. VSD power module temperature low, or sensor open/short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E96	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low. Listed as VSD PFC-IGBT temp low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E97	An internal measurement circuit in the drive has failed. VSD comms ADC failure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E103	The drive's power module is reading abnormally cold, or its sensor circuit is open. VSD power module temperature low or sensor open fault.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E104	The drive shut down after hitting its fault limit too many times. VSD fault limit lockout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Variable Commercial Split (CRV / EVA) and Package PKV160T-240T

Where the code shows: LC7-2 master control and outdoor unit CPU.

Tap your code: E03 E04 E06 E07 E08 E09 E10 E11 E12 E13 E15 E18 E22 E26 E27 E28 E29 E30 E41 E42 E43 E44 E45 E47 E50 E51 E53 E54 E55 E56 E60 E62 E63 E66 E67 E69 E70 E71 E72 E74 E75 E76 E77 E78 E80 E81 E82 E83 E84 E85 E86 E87 E88 E89 E90 E91 E92 E93 E94 E95 E96 E97

Code	What it means	What to do
E03	The room temperature sensor isn't reading properly. Indoor room temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E04	The indoor coil's inlet temperature sensor isn't reading properly. Indoor coil-in temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E06	The compressor is running much hotter than it should. This can point to low refrigerant. High discharge temperature. Trips when discharge temperature exceeds 138 degrees C.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E07	The outdoor coil's temperature sensor isn't reading properly. Outdoor coil temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E08	The compressor outlet temperature sensor isn't reading properly. Discharge temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E09	The low-pressure safety switch has tripped. This often points to low refrigerant. LP switch tripped.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E10	The low-pressure sensor isn't reading properly. LP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E11	The high-pressure safety switch has tripped. HP switch tripped. Blocked outdoor airflow is one common cause.	🔴 Switch the system off at the isolator and call us. It's fine to clear anything blocking the outdoor unit while you wait, but leave the system switched off.
E12	The high-pressure sensor isn't reading properly. HP sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E13	The outdoor unit's inverter drive has reported a fault. Other drive errors.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E15	The outdoor unit and its inverter drive have lost communication. ODU-VSD communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E18	The suction line temperature sensor isn't reading properly. Suction temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E22	The outdoor air temperature sensor isn't reading properly. Ambient temperature sensor error, open or short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E26	The inverter drive has detected too much incoming current. VSD supply/input over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E27	The inverter drive has detected incoming voltage that is too high. VSD supply/input over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E28	The inverter drive is running too hot. VSD temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E29	The incoming power voltage is too low for the inverter drive. VSD low supply voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E30	The inverter drive has locked itself out after repeated faults. VSD trip lock.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E41	The inverter drive's internal DC voltage is too low. VSD DC link voltage low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E42	The system is running with abnormally low suction pressure. This can point to low refrigerant. Envelope protection error: extreme low evaporating pressure.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
E43	The compressor is working outside its safe range (compression ratio too high). Envelope protection error: high compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E44	Pressure on the outdoor coil side is too high for safe operation. Envelope protection error: high condensing pressure.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E45	The compressor is working outside its safe range (compression ratio too low). Envelope protection error: low compression ratio.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E47	The compressor hit its torque limit. Compressor torque limit error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E50	The outdoor unit's control board has a configuration problem. Outdoor board configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E51	The indoor and outdoor units have lost communication with each other. Outdoor-indoor communication error, common after a blackout or power glitch.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E53	The indoor unit and the wall controller have lost communication. Indoor unit to wall controller communication error. Listed as communication error between indoor and master control.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E54	The indoor fan isn't running at the speed the system asked for. Indoor fan RPM feedback error. Listed as loss of Modbus packets from the 485 indoor fan for 30 seconds; clears when packets resume.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
E55	The connection to the building management system has dropped out. BMS to outdoor unit communication error.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E56	The system can't find a master wall controller. No master wall controller detected. Can appear after power interruptions; if it stays, it needs a technician.	🟢 Power-cycle at the isolator: switch off, wait 20 to 30 minutes, switch back on. If the code returns, book a service.
E60	The drive measured too much current going to the compressor. VSD compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E62	The drive's internal DC voltage went too high. VSD DC bus over voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E63	The drive's internal DC voltage went too low. VSD DC bus under voltage.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E66	The incoming power phases are unbalanced, or a phase has dropped out. VSD AC voltage imbalance / AC input loss of phase.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E67	The drive's power electronics reported an internal switching fault. VSD inverter de-saturation.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E69	Part of the drive's power electronics is overheating. VSD PFC-IGBT over temperature.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E70	The drive lost track of the compressor motor's rotation. VSD loss of rotor / lost rotor position.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E71	The compressor motor's temperature sensor is faulty. VSD motor temperature sensor error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E72	A startup relay inside the drive isn't closing properly. VSD precharge relay open.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E74	The drive measured too much current going to the compressor. VSD compressor phase over current. Listed as VSD compressor phase over current.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E75	The drive repeatedly had to wind back compressor current and eventually shut down. VSD compressor phase current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E76	The drive repeatedly had to wind back for module temperature and eventually shut down. VSD power module temperature foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E77	The drive repeatedly had to wind back input current and eventually shut down. VSD AC input current foldback timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E78	The drive's automatic configuration handshake timed out. VSD auto config communication timeout.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E80	The compressor motor is running too hot. VSD motor temperature high.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E81	A circuit board in the drive is running too hot. VSD board temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E82	The drive's power module is running too hot. VSD power module temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E83	Part of the drive's power electronics is running too hot. VSD PFC-IGBT temperature high.	🟡 Clear leaves, covers or plants away from the outdoor unit so air can flow freely, then power-cycle at the isolator. If the code returns, book a service.
E84	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between DSP and PFC.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E85	Two circuit boards inside the drive have stopped talking to each other. Communication error in VSD between comms processor and DSP.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E86	Current to the compressor is unbalanced across its phases. VSD compressor phase current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E87	Current inside the drive's power-correction circuit is unbalanced. VSD 3-phase PFC current imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E88	The drive's electronics or memory have an internal fault. VSD micro-electronic or EEPROM error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E89	The compressor motor ran faster than allowed. VSD motor over speed.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E90	The drive doesn't recognise the compressor it's connected to. VSD compressor model configuration error.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E91	Temperatures inside the drive's inverter section are unbalanced. VSD inverter temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E92	Temperatures inside the drive's power-correction section are unbalanced. VSD PFC temperature imbalance.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E93	The compressor motor is reading abnormally cold. VSD motor temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E94	A circuit board in the drive is reading abnormally cold. VSD board temperature low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E95	The drive's power module is reading abnormally cold, or its sensor is faulty. VSD power module temperature low, or sensor open/short circuit.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E96	Part of the drive's power electronics is reading abnormally cold. VSD PFC-IGBT temperature low. Listed as VSD PFC-IGBT temp low.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
E97	An internal measurement circuit in the drive has failed. VSD comms ADC failure.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Hercules Package System (PKV1400 / PKV1700 / PKV2000)

Where the code shows: Unit controller alarm list (AL numbers).

Tap your code: AL03 AL04 AL05 AL06 AL07 AL08 AL09 AL10 AL11 AL12 AL13 AL17 AL18 AL23 / AL24 AL28-AL31 AL32-AL35 AL210 AL211 AL141 / AL181

Code	What it means	What to do
AL03	The compressor 1 low-pressure sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a warning in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL04	The compressor 1 suction temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a warning in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL05	The compressor 2 low-pressure sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL06	The compressor 2 suction temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL07	The compressor 1 high-pressure sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL08	The compressor 1 outdoor coil temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL09	The compressor 2 high-pressure sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL10	The compressor 2 outdoor coil temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a warning in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL11	The return air temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a warning in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL12	The outside air temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a warning in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL13	The supply air temperature sensor isn't reading properly (faulty wiring, or open/short circuit). Classified as a alarm in the source.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL17	Compressor 1's high/low pressure safety switch has tripped. Trip points: above 4000 kPa or below 300 kPa (PKV1400); above 4502 kPa (PKV1700); above 4000 kPa (PKV2000).	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
AL18	Compressor 2's high/low pressure safety switch has tripped. Same trip points as AL17 for the matching model.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
AL23 / AL24	Compressor 1 or 2 is overloaded (drive alarm, high current). Comp 1 / Comp 2 overload alarm.	🔴 Switch the system off at the isolator and call us. Leave it off until a technician has checked it.
AL28-AL31	One of the supply fans (1-4) has dropped offline. Supply fan device offline, communication loss.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL32-AL35	One of the outdoor fans (1-4) has dropped offline. Outdoor fan device offline, communication loss.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.
AL210	The supply air filter is dirty and due for cleaning. Supply air filter cleaning notification (warning).	🟢 Clean or replace the air filter, then clear the notification. If it returns straight away, book a service.
AL211	Airflow from the supply fan is much lower than expected. Supply air pressure below 15 Pa with fan speed above 250 rpm.	🟡 Check the return-air filter is clean and vents are open, then power-cycle at the isolator. If the code returns, book a service.
AL141 / AL181	One of the inverter drives (VSD 1 / VSD 2) has dropped offline. VSD device offline, communication loss.	🟡 Book a service. A power-cycle at the isolator (off 20 to 30 minutes) is safe to try in the meantime, but if the code returns leave it for the technician.

Code still showing after a reset? Mention the code and your system type when you book and our office can line up the right technician and likely parts before we arrive.

Book a service or call (02) 4760 0100 (24-hour line, Penrith & Blue Mountains).

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