LG Air Conditioner Error Code E455

E455 indicates that the Intelligent Power Module controlling the Fan1 circuit has reached an internal temperature above 85 degrees Celsius. The unit shuts down automatically to prevent damage to this power electronics component. The fault is related to a thermal management problem rather than an electrical failure of the fan itself. A technician needs to inspect the heat sink, mounting bolts, and airflow path to identify the root cause.

No, you should not attempt to continue running the unit while E455 is active. The error causes an automatic shutdown specifically to protect the IPM from damage at high temperatures. Forcing the unit to restart repeatedly without addressing the underlying cause can permanently damage the power module and potentially create a fire or electrical hazard. Allow the unit to cool fully and resolve the thermal issue before attempting to restart.

If the fix involves only cleaning debris from the heat sink or tightening mounting bolts, the cost of a service call is the primary expense, typically in the range of $75 to $150 depending on your location and technician rates. If the thermal compound needs replacement, that adds minimal parts cost. If the IPM itself has failed and requires replacement, total repair costs including parts and labor can range from $200 to $600 or more depending on the specific model and regional labor rates.

Some causes of E455, such as clearing debris from heat sink fins or confirming airflow is not blocked, can be addressed by a knowledgeable DIYer comfortable working with the internal components of an air conditioner. However, checking bolt torque, inspecting the thermal interface material, and assessing the IPM itself require opening the unit and working near high-voltage components, which is best left to a qualified technician. Improper handling of the IPM or its mounting hardware can worsen the problem or create a safety hazard.

A reset may temporarily clear the fault code and allow the unit to restart, but the error will return if the underlying thermal issue has not been corrected. If the heat sink is blocked, the mounting is loose, or the thermal interface is compromised, the IPM will overheat again under normal operating load and trigger E455 again. Address the physical cause of overheating first, then reset the unit.