Perth's Daikin fault code lookup
Daikin fault codes decoded
74 codes covered — what each one means, the likely cause, and whether it's worth trying something yourself before booking. Compiled from Daikin documentation.
Daikin systems report faults as a letter-plus-digit code (A3, E7, U4…) shown on the remote controller or wall controller. The letter tells you which part of the system raised the fault — indoor unit, outdoor unit, sensors, inverter or communications — and the tables below cover the residential range: wall-mounted splits (Cora, Alira, Lite), multi-splits and ducted systems.
How to find your Daikin fault code
Wall splits & multi-splits (wireless remote)
- 1 Point the remote at the indoor unit and hold the Timer CANCEL button for about 5 seconds, until “00” flashes in the temperature display.
- 2 Press Timer CANCEL repeatedly — the display steps through the code list one entry at a time.
- 3 Listen for the beep: a long continuous beep means the code on screen is the stored fault. Short beeps mean keep stepping.
- 4 Hold Timer CANCEL for 5 seconds again to exit. Many newer models also show the code directly on the remote or in the Daikin app.
Ducted systems & wired wall controllers
- 1 Older BRC1C controllers flash the operation light and show the malfunction code directly on the display.
- 2 Newer BRC1E/BRC1H controllers show “Error: Push Menu button” — press Menu/Enter to see the code and which unit raised it.
- 3 The controller’s Main Menu also keeps a fault history, useful if the error cleared before you looked.
Daikin fault code tables
A codes — indoor unit
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| A0 | External protection device activated | A safety or protection device wired to the indoor unit's T1-T2 terminal (e.g. an external interlock on ducted systems) has tripped, or there is a connector/field-setting fault. Common on residential ducted units where an external safety device is fitted. | Book a service |
| A1 | Indoor unit circuit board (PCB) fault — the brain of the indoor unit has failed or been corrupted by electrical noise. | Defective indoor unit PCB; external interference (power surge, electrical noise). | Try this first Power off at the isolator/breaker for 2 minutes and restart — a surge can trip this once. If the code returns, book a technician (PCB replacement). |
| A3 | Drain level control system fault — condensate water isn't draining and the safety float switch has tripped. | Blocked or kinked condensate drain, drain line running uphill, failed drain pump, or faulty float switch. Very common on ducted systems and any split fitted with a drain pump. | Try this first Check the drain outlet outside isn't blocked, kinked or overflowing and that nothing is crushing the drain hose. If water is dripping from the unit or the code returns, book a service — a blocked drain left alone leads to ceiling/wall water damage. |
| A5 | Heat exchanger protection — high-pressure control in heating or anti-freeze (coil icing) protection in cooling has activated. | Most commonly a clogged indoor air filter or blocked airflow; can also be a faulty indoor heat exchanger thermistor. | Try this first Clean the indoor unit filters, make sure vents/returns aren't blocked, then power cycle at the breaker for 2 minutes. If it recurs with clean filters, book a service. |
| A6 | Indoor fan motor fault — the indoor fan is jammed, overloaded or not spinning. | Fan motor failure, broken/shorted motor wiring or loose connector, or a defective indoor PCB. | Book a service |
| A7 | Swing flap (louvre) motor fault — the air-direction flap isn't moving correctly. | Defective swing flap motor, jammed flap cam, loose connection cable, or indoor PCB fault. Unit usually keeps cooling/heating with the flap stuck. | Try this first Check nothing is physically obstructing the louvre, then power cycle for 2 minutes. Not urgent — book a service if the code persists. |
| A9 | Indoor electronic expansion valve fault — the valve that meters refrigerant into the indoor coil isn't responding. | Defective expansion valve coil, wiring/connector fault, or indoor PCB fault. Seen mostly on multi-split and ducted indoor units. | Book a service |
| AF | Drain level above limit (drain system abnormality) / humidifier system malfunction | Water is rising in the drain pan faster than it can clear — clogged or poorly graded drain line, drain pump running continuously, or float/humidifier fault. One of the most common real-world codes on ducted units alongside A3. | Book a service |
| AH | Air-cleaning unit fault — the electrostatic dust collector / streamer air purifier inside the indoor unit has a problem. | Dirty or defective dust-collecting element, contamination on the insulator, or high-voltage supply/PCB fault. | Try this first Remove and clean the air-purification filter/streamer unit per your manual, refit, then power cycle. Book a service if the code returns. |
| AJ | Capacity setting fault (indoor unit PCB) | Capacity setting adaptor missing or wrong, typically after an indoor PCB has been replaced without transferring/fitting the correct adaptor. | Book a service |
C codes — indoor sensors (thermistors)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| C1 | Transmission failure between indoor unit main PCB and fan PCB (sub PCB) | Defective connector or wiring between the indoor main PCB and the fan control/sub PCB, or a failed fan driver board. Seen on current residential wall splits (e.g. FTXM series) and ducted units, often after PCB replacement. | Book a service |
| C4 | Indoor heat exchanger (liquid pipe) temperature sensor fault. | Failed thermistor, loose connector, or indoor PCB fault. | Book a service |
| C5 | Indoor heat exchanger (gas pipe) temperature sensor fault. | Failed thermistor, loose connector, or indoor PCB fault. | Book a service |
| C6 | Indoor fan motor sensor or fan control driver malfunction | Defective fan PCB/driver, faulty fan motor position sensor, or wrong capacity-setting adaptor connection. | Book a service |
| C7 | Front panel drive motor fault — on models with a motorised opening front panel, the panel isn't opening/closing properly. | Defective panel drive motor or limit switch. | Try this first Check nothing is blocking the front panel from opening/closing, then power cycle. Book a service if it persists. |
| C9 | Room (suction/return air) temperature sensor fault — the unit can't read the room temperature. | Failed suction air thermistor, loose connector, or indoor PCB fault. Unit may still run but control temperature poorly. | Book a service |
| CA | Discharge (supply) air temperature sensor fault — mainly on ducted systems. | Failed discharge air thermistor, loose connector, or PCB fault. | Book a service |
| CC | Humidity sensor fault — on models with humidity sensing (e.g. Ururu Sarara). | Defective humidity sensor or connector contact. | Book a service |
| CJ | Temperature sensor inside the remote/wall controller has failed. The system usually keeps running using the indoor unit's own sensor. | Defective controller thermistor or controller PCB; electrical noise. | Book a service |
E codes — outdoor unit
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| E0 | Outdoor unit protection devices actuated (unified protection trip) | A protection device on the outdoor unit has tripped — possible causes include a blocked refrigerant circuit, insufficient refrigerant, or a compressor/fan motor fault. | Book a service |
| E1 | Outdoor unit circuit board (PCB) fault. | Defective outdoor PCB or faulty indoor–outdoor interconnect wiring. | Book a service |
| E3 | High pressure switch has tripped — refrigerant pressure climbed too high and the system shut down to protect itself. Mainly ducted/SkyAir-based systems. | Dirty or blocked outdoor coil, restricted airflow around the outdoor unit, blocked refrigerant piping, or a faulty switch/connector. | Try this first Switch off, clear leaves/debris and anything stacked around the outdoor unit so it can breathe, then power cycle for 2 minutes. If it trips again, book a service. |
| E4 | Low pressure switch has tripped — refrigerant pressure fell abnormally low. | Refrigerant loss/undercharge, blocked piping, or a faulty low-pressure sensor/switch. | Book a service |
| E5 | Inverter compressor motor lock or overheat — the compressor is straining or has seized. | Compressor lock, excessive pressure differential, inverter PCB fault, or compressor wiring (UVW) error. | Switch off & call |
| E6 | Compressor won't start (motor lock) on wall-mounted splits; on ducted systems, fixed-speed compressor overcurrent or lock. | Defective compressor, control PCB fault, or refrigerant stop valve left closed after installation. | Switch off & call |
| E7 | Outdoor fan motor fault — the outdoor fan is jammed or its motor/wiring has failed. | Fan motor failure, loose or disconnected fan motor connector, or debris (leaves, sticks) physically jamming the fan. | Try this first Switch off at the breaker first, then check nothing is caught in the outdoor fan and clear debris around the unit. Power back on after 2 minutes; if the code returns, book a service. |
| E8 | Overcurrent detected. On wall-mounted splits (Cora, Alira, Lite) this is overcurrent on the incoming power side of the inverter; on ducted systems it means compressor overcurrent. | Wall splits: power supply or mains voltage problems, inverter main-circuit capacitor or outdoor PCB fault. Ducted: compressor drawing excessive current. | Switch off & call |
| E9 | Outdoor electronic expansion valve coil fault. | Disconnected connector, defective valve coil, or outdoor control PCB fault. Common on multi-splits and ducted. | Book a service |
| EA | Four-way (reversing) valve fault — the unit can't switch properly between heating and cooling. | Defective four-way valve, refrigerant shortage, faulty thermistor, or outdoor PCB fault. | Book a service |
F codes — refrigerant circuit protection
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| F3 | Discharge pipe temperature fault — the compressor discharge is running dangerously hot. | Low refrigerant (leak) driving discharge temperature up, or a faulty discharge pipe thermistor/PCB. Continued running risks compressor damage. | Switch off & call |
| F6 | Abnormally high pressure / refrigerant overcharge detected (cooling). | Refrigerant overcharged at installation, or a disconnected heat exchanger / outdoor air / liquid pipe thermistor; outdoor PCB fault. | Book a service |
H codes — outdoor sensors and switches
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| H0 | Compressor sensor system fault — a sensor monitoring the compressor has failed or is disconnected. | Disconnected/poorly connected sensor harness or defective PCB. | Book a service |
| H3 | High pressure switch itself is faulty (not tripped — broken). | Defective HPS, broken wire, connector or outdoor PCB fault. | Book a service |
| H4 | Low pressure switch (LPS) malfunction | Defective low pressure switch, broken wire, or connector fault on the outdoor unit. Counterpart to H3 (high pressure switch), documented in SkyAir-based residential ducted service data. | Book a service |
| H6 | Compressor position detection sensor fault — the inverter can't sense the compressor rotor position, so the compressor won't start reliably. | Poor contact on the compressor cable, defective compressor, or outdoor PCB fault. Sometimes triggered one-off by a voltage dip. | Try this first Power off at the breaker for 2 minutes and restart once. If H6 comes back, stop and book a technician — repeated starts against this fault stress the compressor. |
| H7 | Outdoor fan motor signal fault — the fan runs but its feedback signal is abnormal. | Fan motor circuit failure, broken/shorted fan motor leads or disconnected connector, inverter PCB fault. | Book a service |
| H8 | Compressor input current (CT) sensor system fault. | Defective power transistor, reactor, inverter wiring, or outdoor PCB. | Book a service |
| H9 | Outdoor air temperature sensor fault. | Failed outdoor air thermistor, loose connector, or outdoor PCB fault. | Book a service |
J codes — outdoor thermistors and pressure sensors
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| J1 | Refrigerant pressure sensor fault (ducted/multi systems). | Defective pressure sensor or connector, or outdoor PCB fault. | Book a service |
| J2 | Compressor current sensor fault. | Defective current sensor, compressor, or outdoor PCB. | Book a service |
| J3 | Discharge pipe temperature sensor fault. | Failed discharge pipe thermistor, loose connector, or outdoor PCB fault. | Book a service |
| J5 | Suction pipe temperature sensor fault. | Failed suction pipe thermistor, loose connector, or outdoor PCB fault. | Book a service |
| J6 | Outdoor heat exchanger temperature sensor fault. | Failed heat exchanger thermistor, loose connector, or outdoor PCB fault. | Book a service |
| J7 | Refrigerant circuit (liquid pipe) temperature sensor fault — mainly multi-split/ducted. | Failed liquid pipe thermistor, loose connector, or outdoor PCB fault. | Book a service |
| J8 | Refrigerant circuit (liquid pipe) temperature sensor fault. | Failed liquid pipe thermistor, loose connector, or outdoor PCB fault. | Book a service |
| J9 | Refrigerant circuit (gas pipe) temperature sensor fault. | Failed gas pipe thermistor, loose connector, or outdoor PCB fault. | Book a service |
| JA | High pressure sensor fault (ducted/multi systems). | Defective high pressure sensor, swapped sensor connections, or outdoor PCB fault. | Book a service |
| JC | Low pressure sensor fault (ducted/multi systems). | Defective low pressure sensor, swapped sensor connections, or outdoor PCB fault. | Book a service |
L codes — inverter (outdoor power electronics)
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| L1 | Inverter circuit board fault. | Defective inverter PCB, blown fuse, compressor wiring fault, or outdoor fan motor fault. | Book a service |
| L3 | Electrical component box overheating — the outdoor unit's control box got too hot. | Restricted airflow/recirculation over the outdoor unit (short circuit of hot air), failed outdoor fan motor, power transistor or PCB fault. | Try this first Clear debris and vegetation so the outdoor unit has free airflow (and shade if it's in extreme sun), then power cycle for 2 minutes. Book a service if it recurs. |
| L4 | Inverter heat sink (radiation fin) overheating. | Hot-air recirculation or blocked airflow raising fin temperature, or a defective fin thermistor. | Try this first Make sure the outdoor unit's airflow isn't blocked and clear any debris, then power cycle for 2 minutes. If L4 returns, book a service. |
| L5 | Inverter instantaneous overcurrent (DC) — a sudden current spike, often pointing to a compressor winding or startup fault. | Compressor coil defect (broken wire or insulation failure), mechanically locked compressor, or inverter PCB fault. | Switch off & call |
| L8 | Inverter compressor overcurrent — the compressor is overloaded. | Compressor overload, broken compressor coil wiring, disconnected compressor wiring, or inverter PCB fault. | Switch off & call |
| L9 | Inverter compressor startup error (stall prevention) — the compressor tries to start but stalls. | Stop valve not opened, wiring errors to the compressor, large pressure differential at startup, defective compressor or inverter PCB. | Book a service |
| LC | Communication fault between the outdoor control board and inverter board. | Loose connection between inverter and control PCBs, electrical noise, defective inverter compressor or PCB. | Book a service |
P codes — inverter power supply and sensors
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| P1 | Power voltage imbalance or open phase — the incoming power supply to the outdoor unit is abnormal. | Open phase (3-phase systems), voltage imbalance between phases, defective main-circuit capacitor or wiring, or inverter PCB fault. | Book a service |
| P3 | Switch box (reactor) temperature sensor fault. | Failed thermistor, loose connector, or inverter PCB fault. | Book a service |
| P4 | Inverter heat sink (radiation fin) temperature sensor fault. | Defective fin thermistor, inverter PCB, compressor or fan motor fault. | Book a service |
| PJ | Capacity setting fault (outdoor unit PCB) | Capacity setting adaptor missing or incorrect on the outdoor PCB, typically after an outdoor board replacement. | Book a service |
U codes — system and communication
| Code | What it means | Likely cause | What to do |
|---|---|---|---|
| U0 | Refrigerant shortage — the system has detected it is low on gas (a leak somewhere in the circuit). | Refrigerant leak or blocked/incorrect piping; less commonly a faulty thermistor, low pressure sensor or outdoor PCB. Running low on gas overheats and damages the compressor. | Switch off & call |
| U1 | Reverse phase / open phase — the 3-phase power supply is wired in the wrong sequence or a phase is missing (3-phase ducted systems). | Power supply phase reversal, missing phase at the supply, or outdoor PCB fault. | Book a service |
| U2 | Power supply voltage problem or momentary power failure detected. | Abnormal supply voltage, brownout/blackout event, or main circuit wiring defect. | Try this first Often appears after a blackout or voltage dip. Power off at the breaker for 2 minutes and restart. If it keeps appearing without power interruptions, book a service. |
| U3 | Check operation (test run) not executed — the installer's commissioning test hasn't been completed. Mainly ducted/multi systems. | System commissioning step skipped or a transmission error during setup. | Book a service |
| U4 | Communication failure between the indoor and outdoor units. | Wiring fault or short in the indoor–outdoor interconnect cable, outdoor unit power switched off, address mismatch, or a failed indoor/outdoor PCB. | Try this first Check the outdoor unit's isolator/breaker hasn't been switched off, then power both units off at the breaker for 2–5 minutes and restart. If U4 returns, book a service. |
| U5 | Communication failure between the indoor unit and the remote/wall controller. | Controller wiring fault, two controllers both set as 'main', electrical noise, or defective indoor/controller PCB. | Try this first Power cycle at the breaker for 2 minutes. If the controller still shows U5 or stays blank, book a service. |
| U6 | Communication failure between indoor units | Faulty inter-unit wiring, indoor PCB defect, or electrical noise — relevant to multi-split installations and ducted systems with multiple indoor controllers. | Book a service |
| U7 | Communication failure between outdoor units (multi-outdoor installations). | Transmission wiring connection error between outdoor units or a defective outdoor PCB. | Book a service |
| U8 | Communication failure between remote controllers (main/sub setup). | Main/sub controller setting error, wiring between controllers, or defective controller PCB. | Book a service |
| U9 | Fault in another indoor unit on the same system (multi-split/ducted) — this unit is fine but a partner unit or its wiring has an issue. | Transmission error or expansion valve/PCB fault on another indoor unit sharing the outdoor unit. | Book a service |
| UA | Improper combination of indoor and outdoor units — the connected units don't match. | Too many indoor units connected (multi-split), mismatched refrigerant types or models, or PCB settings not configured after a board replacement. | Book a service |
| UC | Centralised control address setting fault (systems with central controllers). | Duplicated centralised control address or defective indoor PCB. | Book a service |
| UE | Communication failure between indoor unit and centralised control equipment. | Transmission wiring or connector fault, or defective central controller/indoor PCB. | Book a service |
| UF | System not set up / wiring–piping mismatch — the refrigerant piping and communication wiring don't correspond. | Interconnect wiring crossed between systems during installation, check operation never run, stop valve not opened, or defective indoor PCB. | Book a service |
| UH | System malfunction — the system configuration itself is inconsistent. | Improper indoor–outdoor / outdoor–outdoor transmission wiring, or defective indoor/outdoor PCB. | Book a service |
No matching code found.
Meanings vary by series and some codes are model-specific — call 0434 951 341 with the code and your model number and we'll decode it.
Reference compiled from Daikin service and operation documentation. Codes and meanings are provided as general guidance for the Australian residential range and can differ between model series; no affiliation with Daikin is implied.
Tell us the code when you book — diagnosis starts before we arrive
Air conditioning service and repairs across Perth from $220 inc GST — all brands, splits and ducted. Quoting the fault code gives us a head start on where to look; we then test and confirm the actual fault on site before any part is ordered, so you never pay for a part you didn't need.
Frequently Asked Questions
How do I find the fault code on my Daikin?
On wall-mounted splits: point the remote at the unit and hold the Timer CANCEL button for about 5 seconds until “00” flashes in the display, then press it repeatedly — the unit gives a long beep when the displayed code matches the stored fault. On ducted systems the wall controller shows the code directly (newer BRC1E/BRC1H controllers show it under the Menu button). The full steps are above the tables on this page.
Does a Daikin fault code mean my system needs replacing?
Rarely. Most codes point to a specific repairable fault — a blocked drain, a fan motor, a sensor. Even compressor-related codes are often caused by something cheaper (a closed stop valve, a dirty coil, power supply issues). Diagnosis first, always.
Can I clear a Daikin fault code myself?
Power-cycling at the isolator or breaker for two minutes clears many one-off trips, and it's a safe first step for most codes marked “Try this first” in our tables. If the code returns, the fault is real — repeated resets without fixing the cause can turn a small repair into a compressor-sized one.
My Daikin shows a code that isn't in this list — what now?
Meanings can vary between model series, and some codes are specific to commercial (VRV/SkyAir) equipment. Call us on 0434 951 341 with the code and your model number (on a sticker on the indoor unit) and we'll tell you what it means for your exact system.
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