LG Air Conditioner Error Code 3

Error code 3 on an LG multi-split air conditioner indicates that the system detected simultaneous cooling and heating mode commands from different indoor zones. Because the outdoor unit can only operate in one mode at a time, it triggers this error and resets the remote control to clear the conflict. It is a system protection response, not typically a hardware failure.

A reset can temporarily clear error code 3, and the system itself initiates a remote control reset as part of its response to this error. However, if the underlying mode conflict is not resolved before restarting, the error will return. Make sure all indoor zone modes are set consistently before powering the system back on.

If the error is caused by a simple mode conflict between zones, there is no parts cost and the fix requires only adjusting the remote settings. If a wiring or PCB fault is responsible, repair costs can range from around 100 to 500 dollars or more depending on which component needs replacement and local labor rates. A diagnostic visit from a qualified technician typically costs between 75 and 150 dollars.

Start by checking the mode setting on every indoor unit remote or wall controller in the system and make sure all units are set to the same mode, either all cooling or all heating. Turn the system off completely, correct the mode settings, and then restart. If the error returns even after aligning all modes, inspect the communication wiring between indoor and outdoor units for loose connections or damage.

Error code 3 is primarily a system conflict notification rather than a safety hazard. The system shuts down the conflicting operation to protect the compressor and refrigerant circuit from running under contradictory conditions. Addressing the mode conflict promptly is recommended to avoid repeated cycling and unnecessary wear on the system.