Daikin Aircon Error Codes

No malfunction detected (normal status)

No malfunction detected in self-diagnosis mode · Temporary status after a diagnostic check or reset · Issue may be intermittent if cooling complaint still exists

Indoor unit PCB or control abnormality

System control logic detected abnormal operation · Wiring/communication mismatch · Controller or PCB fault

Indoor and outdoor unit mismatch

System control logic detected abnormal operation · Wiring/communication mismatch · Controller or PCB fault

Indoor unit transmission error

Loose or reversed interconnection wiring · Poor terminal contact/corrosion · Indoor/outdoor PCB communication circuit fault · Power instability

Indoor refrigerant temperature sensor abnormal

Temperature sensor open/short · Sensor connector loose · Sensor circuit fault on indoor PCB

Indoor air temperature sensor abnormal

Temperature sensor open/short · Sensor connector loose · Sensor circuit fault on indoor PCB

Abnormal water level in thermal storage unit

Abnormal water level signal from storage tank · Level sensor fault or wiring issue · Control board interpretation error

Radiation/auxiliary fan system malfunction

Radiation fan or auxiliary fan circuit fault · Fan motor/driver PCB problem · Communication issue in fan control chain

Indoor PCB fault

Indoor PCB/component failure · Loose or oxidised internal connectors · Moisture or surge damage on control board

Drain water level fault / drainage problem

Blocked drain pipe or trap · Faulty or stuck drain pump/float switch · Heavy dirt buildup in drain pan

Indoor heat exchanger overheat/freeze protection triggered

Dirty indoor coil or filter reducing airflow · Low refrigerant charge from leak · Indoor thermistor reading out of range

Indoor fan motor lock or overload

Fan motor lock or winding fault · Motor connector loose or damaged · Indoor PCB drive circuit fault

Swing flap motor fault

Swing flap motor jammed or faulty · Disconnected swing motor harness · Indoor PCB output fault

Indoor overcurrent or abnormal AC input

Abnormal indoor input current or power surge · Wiring short or poor terminal contact · Indoor power circuit/PCB fault

Electronic expansion valve (EEV) fault

Electronic expansion valve stuck or coil faulty · Valve harness disconnection · Control PCB drive fault

Capacity setting or addressing error

Incorrect indoor/outdoor capacity setting · DIP switch or field setting mismatch · Control PCB setting error

Drain water level sensor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Indoor heat exchanger thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Liquid pipe thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Indoor fan motor thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Indoor suction air thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Radiation thermistor resistance abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Remote controller thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Outdoor protection device activated

Outdoor protection device triggered · Compressor or fan motor electrical fault · Refrigerant circuit abnormality

High pressure protection activated

Dirty condenser or blocked outdoor airflow · Outdoor fan problem · Refrigerant overcharge or non-condensables

Low pressure protection activated

Low refrigerant due to leak · Expansion device or piping restriction · Insufficient heat load or sensor/control fault

Compressor overload / overcurrent protection

Compressor overcurrent or thermal overload · Voltage instability or wiring fault · Refrigerant restriction causing high load

Compressor lock or startup failure

Compressor lock/start failure · Inverter drive fault · Mechanical compressor fault

Outdoor fan motor lock fault

Outdoor fan motor lock · Fan motor connector/drive fault · Outdoor PCB failure

Outdoor overcurrent protection

Outdoor unit current spike · Compressor winding or power module issue · Power supply instability

Low refrigerant or suction temperature abnormal

Low refrigerant due to leak · Expansion device or piping restriction · Insufficient heat load or sensor/control fault

Outdoor discharge pipe temperature too high

Restricted refrigerant flow or low charge · Discharge thermistor abnormal · Compressor running under high load

Outdoor heat exchanger temperature high

Restricted refrigerant flow or low charge · Discharge thermistor abnormal · Compressor running under high load

High pressure switch fault

Dirty condenser or blocked outdoor airflow · Outdoor fan problem · Refrigerant overcharge or non-condensables

Low pressure switch fault

Low refrigerant due to leak · Expansion device or piping restriction · Insufficient heat load or sensor/control fault

Compressor position sensor fault

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Outdoor air temperature thermistor fault

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Refrigerant pressure sensor fault

Pressure sensor faulty or out of calibration · Sensor wiring issue · Outdoor PCB input fault

Discharge pipe thermistor fault

Pipe thermistor fault or displacement · Refrigerant circuit anomaly · Sensor harness/PCB input fault

Suction pipe thermistor fault

Pipe thermistor fault or displacement · Refrigerant circuit anomaly · Sensor harness/PCB input fault

Outdoor heat exchanger thermistor fault

Pipe thermistor fault or displacement · Refrigerant circuit anomaly · Sensor harness/PCB input fault

Discharge pressure sensor fault

Pressure sensor faulty or out of calibration · Sensor wiring issue · Outdoor PCB input fault

Suction pressure sensor fault

Pressure sensor faulty or out of calibration · Sensor wiring issue · Outdoor PCB input fault

Inverter system fault

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

Electrical parts overheating in inverter section

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

Inverter heatsink temperature too high

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

Inverter overcurrent / compressor lock protection

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

Power transistor (IPM) fault

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

Phase loss or voltage imbalance (3-phase)

Phase loss or reverse phase on supply · Voltage imbalance · Main power wiring fault

Inverter heatsink thermistor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

DC current sensor abnormal

Thermistor/sensor open or short circuit · Loose or disconnected sensor connector · Sensor harness damage or PCB input fault

Inverter main circuit DC voltage abnormal

Inverter IPM/power transistor fault · Compressor electrical abnormality · Heatsink overheating or weak airflow · Supply voltage fluctuation

AC input overcurrent

Outdoor unit current spike · Compressor winding or power module issue · Power supply instability

Field setting / capacity setting fault

Incorrect indoor/outdoor capacity setting · DIP switch or field setting mismatch · Control PCB setting error

Refrigerant shortage or suction temperature abnormal

Low refrigerant due to leak · Expansion device or piping restriction · Insufficient heat load or sensor/control fault

Reverse phase power supply

Phase loss or reverse phase on supply · Voltage imbalance · Main power wiring fault

Power supply fault (voltage drop/open phase)

Phase loss or reverse phase on supply · Voltage imbalance · Main power wiring fault

Check operation not completed / test run setting error

Indoor/outdoor model combination mismatch · Addressing or field setting error · PCB setup/configuration fault

Communication error between indoor and outdoor units

Loose or reversed interconnection wiring · Poor terminal contact/corrosion · Indoor/outdoor PCB communication circuit fault · Power instability

Communication error between indoor unit and remote controller

Remote-controller cable loose/damaged · Remote controller board fault · Indoor PCB communication fault

Communication error between outdoor units

Loose or reversed interconnection wiring · Poor terminal contact/corrosion · Indoor/outdoor PCB communication circuit fault · Power instability

Indoor/outdoor combination or setting mismatch

Indoor/outdoor model combination mismatch · Addressing or field setting error · PCB setup/configuration fault

System addressing/initialisation communication fault

Indoor/outdoor model combination mismatch · Addressing or field setting error · PCB setup/configuration fault