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.

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CH00System

General fault indication requiring inspection

Temporary power fluctuation or electrical noise · Startup self-check detected abnormal condition · Underlying fault pending full diagnosis

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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Other diagnostic tools

If your unit shows a different problem or a blinking pattern instead, try a different starting point.

Blinking lights

LED blinking in a pattern? Match it to the likely fault.

Aircon problems

Diagnose a specific problem like no cooling, water leak, or noise.

LG brand hub

Guides, resources, and model info for LG aircon.

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