Daikin Error Codes
Daikin splits (FTX/FTXM) and VRV display 2-character codes on the BRC controller or by indoor LED flashes.
A1
Indoor PCB defect
- Cause:
- Indoor main PCB failure
- Action:
- Power-cycle; replace indoor PCB if persists.
A3
Drain level abnormal
- Cause:
- Float switch tripped / drain pump failed
- Action:
- Clear drain, test pump and float.
A5
Indoor freeze-up / overheat protection
- Cause:
- Low airflow, dirty filter, low charge
- Action:
- Clean filter & coil, check fan, charge.
A6
Indoor fan motor fault
- Cause:
- Stalled or failed DC fan motor
- Action:
- Test motor and PCB feedback signal.
C4
Indoor liquid pipe thermistor (R2T) fault
- Cause:
- Open / short sensor
- Action:
- Replace liquid pipe sensor.
C5
Indoor gas pipe thermistor (R3T) fault
- Cause:
- Open / short sensor
- Action:
- Replace gas pipe sensor.
C9
Indoor suction air thermistor (R1T) fault
- Cause:
- Open / short sensor
- Action:
- Replace suction sensor.
E1
Outdoor PCB defect
- Cause:
- Outdoor main PCB failure
- Action:
- Replace outdoor PCB.
E3
High pressure switch activated
- Cause:
- Blocked condenser, overcharge, fan fault
- Action:
- Inspect condenser, fan, charge, EEV.
E4
Low pressure switch activated
- Cause:
- Undercharge, blocked filter drier
- Action:
- Leak test, check filter drier and EEV.
E5
Compressor motor lock / overload
- Cause:
- Locked rotor or compressor failure
- Action:
- Megger compressor, test inverter.
E6
Compressor startup failure
- Cause:
- Low DC bus, IPM, locked rotor
- Action:
- Check supply, inverter PCB, compressor.
E7
Outdoor fan motor fault
- Cause:
- Stalled / failed fan motor
- Action:
- Test fan motor and driver.
F3
Discharge pipe temperature too high
- Cause:
- Low charge, EEV stuck closed
- Action:
- Check charge, EEV, Td sensor.
H6
Position sensor fault (compressor)
- Cause:
- Inverter PCB or compressor fault
- Action:
- Replace inverter PCB.
L5
Compressor IPM overcurrent (instantaneous)
- Cause:
- Locked rotor, IPM short
- Action:
- Megger compressor, replace inverter.
U0
Refrigerant shortage
- Cause:
- Loss of refrigerant charge
- Action:
- Leak test and recharge to spec.
U2
Power supply voltage abnormal
- Cause:
- Low/high mains or DC bus drop
- Action:
- Measure supply, check rectifier / DC bus.
U4
Indoor ↔ outdoor transmission error
- Cause:
- F1/F2 wiring or PCB fault
- Action:
- Check F1/F2 polarity, length and PCBs.
UA
Indoor/outdoor mismatch
- Cause:
- Incompatible combination or too many units
- Action:
- Check pairing and quantity vs spec.
For field guidance only. Codes and procedures vary by model and firmware — always confirm with the Daikin service manual for the specific unit before carrying out a repair.