LG Air Conditioner Error Code 04

Error code 04 on an LG air conditioner indicates a drain pump malfunction. Specifically, the float switch inside the condensate drain pan has opened because the water level rose to approximately half the height of the float switch body. This happens when the drain pump fails or the drain pipe becomes clogged, and the unit stops operating to prevent water overflow.

No, you should not attempt to bypass or continue running the unit while error code 04 is active. The code indicates that condensate water is accumulating at an unsafe level, and continued operation without resolving the drainage problem can lead to water overflow, water damage to walls or ceilings, and potential electrical hazards inside the unit.

A power reset may temporarily clear the error code and allow the unit to restart, but the code will return as soon as the condensate water level rises again if the underlying problem has not been fixed. The float switch will reopen and trigger code 04 again until the drain pump is repaired or the drain line is cleared. Always address the root cause before relying on a reset.

Start by inspecting the condensate drain pan to confirm the water level is elevated. If water is present, clear any blockage in the drain line by flushing it out, and check the drain pump for debris or failure. If the drain pan is empty despite the code appearing, inspect the float switch and its wiring connections for faults. Replacing a failed drain pump or clearing a blocked drain line will typically resolve the error.

Repair costs depend on the root cause. If only a drain line cleaning is needed, professional service typically runs between $75 and $200. Replacing a faulty drain pump generally costs between $150 and $400 including parts and labor, depending on the model and service rates in your area. A failed float switch is usually a lower-cost repair, often in the $100 to $250 range with labor.