LG Air Conditioner Error Code E401

E401 on an LG air conditioner signals that the indoor evaporator coil has reached a freezing condition, triggering the system to stop the outdoor compressor as a protective measure. The unit enters this mode to prevent ice buildup from causing further damage or blocking airflow completely. The error will persist until the underlying airflow or refrigerant issue is corrected and the coil temperature returns to a safe level.

Resetting the unit by powering it off and back on may temporarily clear the E401 code, but the error will return if the root cause is not addressed. Allow any ice on the evaporator to fully melt before restarting, which can take 30 to 60 minutes with the fan running in fan-only mode. A reset is only a lasting fix if the triggering condition, such as a blocked grille or clogged filter, has been corrected first.

If the fix is as simple as clearing a blocked grille or cleaning a dirty filter, there is no parts cost involved. A fan motor replacement typically ranges from around 150 to 400 dollars including labor, depending on the model and technician rates. If the issue involves a refrigerant leak, costs can range from 200 to 600 dollars or more, covering leak detection, repair, and recharging the system.

Start by checking that all indoor unit grilles are fully open and free of obstructions, and confirm that the indoor fan is running when the unit is operating. Clean or replace the air filter if it is clogged. If the grilles are clear and the fan is working normally, the issue may be low refrigerant or a faulty fan motor, both of which require a qualified technician to diagnose and repair.

You should not continue running the unit in cooling mode while E401 is active. A frozen evaporator coil can cause liquid refrigerant to return to the compressor, potentially damaging it. The compressor stop function is designed to protect the system, and bypassing or repeatedly resetting it without fixing the cause can lead to compressor failure and costly repairs.