40 LG ac error codes and troubleshooting (FULL LIST)

Is your LG air conditioner suddenly blowing warm air, shutting down entirely, or flashing a cryptic alphanumeric code like CH05, CH21, or C4 on the digital display? A malfunctioning AC always feels like an emergency, but those flashing letters and numbers are your system’s built-in self-diagnosis tool pinpointing the exact mechanical or electrical failure.

LG’s diagnostic matrix uses a highly specific format, almost exclusively displaying “C” or “CH” (Cooling/Heating) codes. These codes intelligently separate basic sensor glitches (like a CH01 room temperature sensor fault) from severe inverter module issues (like a CH21 overcurrent protection) and communication drops between the indoor and outdoor units (CH05).

Instead of hunting down the correct user manual for your specific generation of LG AC, use our Official LG AC Error Code Decoder below. We have compiled the complete master list of the 40 most critical LG error codes. Simply select your flashing code to instantly reveal the hidden cause and the step-by-step DIY or professional solution.

⚠️ Pro Safety Tip: While issues like checking your remote control wiring (CH03) or noticing a “PO” code (which simply means Power Mode) are safe DIY checks, errors involving Inverter DC Power Overcurrents (CH21/C6), Heat Sink Thermistors (CH62), or Compressor Damage (CH73) should always be handled by our licensed HVAC technicians to prevent severe electrical hazards.

LG inverter air conditioner error codes