CH00System
General fault indication requiring inspection
Temporary power fluctuation or electrical noise · Startup self-check detected abnormal condition · Underlying fault pending full diagnosis
LG Aircon Error Codes
Learn what common LG error codes mean, what typically causes them, and whether they need urgent attention.
LG code table
This is a guidance table, not a model-exact diagnosis. The same code can differ by series, controller, and model year. Use this page to narrow next steps, then verify with model sticker details.
Safety Warning
Stop using the unit and contact a technician if the breaker trips repeatedly, you smell burning, see sparks, hear loud electrical buzzing, or water is leaking from places it normally should not.
CH01Sensor
Indoor air temperature sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH02Sensor
Indoor pipe temperature sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH03System
Refrigerant absence or severe refrigerant-flow abnormality
Refrigerant shortage due to leak at flare joint or piping · Restriction in expansion valve or refrigerant circuit · Compressor protection triggered by low suction condition
CH04Indoor
Drainage/full-water-level error
Drain pump not operating or drain path blocked · Condensate tank or drain pan reached full level · Float switch/level sensor abnormality
CH05Communication
Communication error between indoor and outdoor units
Loose, reversed, or damaged communication wiring between indoor and outdoor units · Poor terminal contact or corroded wire joints · Indoor or outdoor PCB communication circuit fault · Power instability during operation or after installation
CH06Sensor
Outdoor pipe temperature sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH07System
Operating-mode conflict across connected indoor units
Connected indoor units are set to conflicting operation modes · One unit in heating while another is in cooling/dehumidify mode · Mode state mismatch after power recovery in multi-split system
CH09Indoor
Indoor PCB/control board fault
Indoor control board, fan, or drainage component fault · Loose connectors or internal wiring issue · Drain blockage, float-switch, or pump abnormality · Airflow restriction causing protection trip
CH10Indoor
Indoor BLDC fan motor lock or fan drive fault
Indoor BLDC fan motor locked or failing · Fan wheel jammed by dirt/debris · Fan motor drive circuit or indoor PCB fault · Wiring harness or connector loosened
CH12Sensor
Indoor thermistor disconnected/abnormal
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH21Inverter
Compressor overcurrent / IPM protection
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH22Inverter
Current sensing value too high (CT protection)
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH23Inverter
Low DC link voltage in inverter circuit
DC link voltage dropped below safe threshold · Inverter module or capacitor deterioration · Power supply sag or unstable mains voltage
CH24Outdoor
Pressure switch or pressure protection fault
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH25Inverter
AC input voltage abnormal (high/low)
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH26Inverter
Compressor position/drive abnormal
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH27Inverter
Power/current sensing circuit fault (PSC)
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH28Inverter
DC link high-voltage protection
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH29Inverter
Compressor overcurrent protection
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH31Inverter
Inverter compressor over-temperature protection
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH32Outdoor
Compressor discharge temperature too high
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH33Sensor
Discharge temperature sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH34Outdoor
High-pressure protection activated
High condensing pressure from blocked outdoor airflow · Outdoor coil heavily soiled or fan underperforming · Refrigerant overcharge or non-condensable gas in circuit
CH35Outdoor
Low-pressure protection activated
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH36Outdoor
Compressor discharge temperature protection (outdoor)
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH37Outdoor
Low-pressure switch open fault
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH38System
Refrigerant shortage (low gas) detected
Low refrigerant charge from leak in piping or flare joints · Service valves not fully opened after installation/relocation · Refrigerant flow restriction causing low-pressure condition
CH39Sensor
PCB or CT sensor open/abnormal
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH40Sensor
Current transformer (CT) sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH41Sensor
Compressor discharge thermistor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH44Sensor
Outdoor air thermistor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH45Sensor
Outdoor middle-pipe thermistor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH46Sensor
Outdoor suction-pipe thermistor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH48Sensor
Compressor discharge-pipe thermistor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH53Communication
Communication error between main and sub PCB
Loose or damaged interconnection cable between indoor and outdoor units · Poor terminal contact or wiring corrosion · Indoor or outdoor PCB communication circuit fault · Power supply instability
CH54System
Phase/reverse-phase power wiring error
Reverse phase sequence (R/S/T) after electrical work · One supply phase missing at outdoor unit terminal · Incorrect breaker-box wiring to dedicated AC circuit
CH60Outdoor
Outdoor EEPROM or memory fault
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH61Outdoor
Condenser/heat-exchanger over-temperature protection
Condenser airflow blocked or outdoor coil heavily dirty · Outdoor fan motor/driver abnormality · Refrigerant pressure or flow imbalance · Outdoor control board protection triggered
CH62Inverter
Inverter heatsink temperature too high
Inverter IPM/power module abnormality · Compressor electrical overload or lock condition · DC link voltage/current abnormality · Power fluctuation causing inverter protection trip
CH63Sensor
Condenser pipe sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH65Sensor
Heatsink temperature sensor open/short
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
CH66Outdoor
Outdoor BLDC fan motor lock / fan fault
Outdoor fan motor lock or rotor resistance · Fan driver output fault on outdoor PCB · Physical obstruction or severe coil heat load
CH67Outdoor
BLDC fan motor lock protection
BLDC fan motor lock or startup failure · Fan motor feedback (Hall) signal abnormal · Outdoor PCB fan-drive circuit fault
CH90System
Test-run protection error (installation/piping/power related)
Installation test-run detected piping/refrigerant abnormality · Compressor load protection triggered during commissioning · Temporary power instability during startup
CH91System
Test-run protection error (installation/piping/power related)
Installation test-run detected piping/refrigerant abnormality · Compressor load protection triggered during commissioning · Temporary power instability during startup
CH93Communication
Indoor-outdoor communication instability
Indoor-outdoor communication line instability · Outdoor unit not receiving power on newer split-power models · Wiring/connector fault or communication PCB issue
F1General
Indoor floor-standing model system fault (F1)
Model-specific protection or control logic detected abnormal operation · Internal wiring or component fault · Control PCB requires professional diagnosis
F2General
Indoor floor-standing model system fault (F2)
Model-specific protection or control logic detected abnormal operation · Internal wiring or component fault · Control PCB requires professional diagnosis
F3General
Indoor floor-standing model system fault (F3)
Model-specific protection or control logic detected abnormal operation · Internal wiring or component fault · Control PCB requires professional diagnosis
FLIndoor
Condensate tank full / float-level protection
Condensate tank reached full level in high-humidity operation · Drain outlet blocked or drain cap not fitted correctly · Float or level-sensing circuit issue
P2Sensor
Room temperature sensing/control abnormality
Thermistor or sensor open/short circuit · Loose sensor connector or damaged harness · Sensor out-of-range due to heat/moisture stress · Control PCB sensor input fault
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