LG Heat Pump Error Code E353

E353 indicates a high pressure sensor breakaway fault. The control board has detected that the high pressure sensor has lost its electrical connection or signal, so the system shuts down compressor operation to prevent unmonitored refrigerant pressure from causing damage. This is typically a wiring, connector, or sensor issue rather than a refrigerant pressure problem.

No. The system is designed to shut down when E353 is active because it cannot safely monitor high-side refrigerant pressure without a functioning sensor. Attempting to bypass this protection and run the compressor could result in dangerously high refrigerant pressures, compressor damage, or refrigerant circuit failure. Leave the unit off until the fault is resolved.

Repair costs vary depending on the root cause. If only a reconnection or connector cleaning is needed, a service call fee of roughly $75 to $150 may cover the work. Replacing a high pressure sensor typically adds $50 to $200 in parts. If the control board is at fault, total repair costs including parts and labor can range from $300 to $700 or more depending on the model.

A knowledgeable DIYer can safely inspect the sensor wiring harness and connector for obvious disconnection, corrosion, or physical damage. However, replacing the high pressure sensor or working near refrigerant lines involves pressurized systems and should be handled by a certified technician. If the wiring appears intact and the fault persists, professional diagnosis is recommended.

A power reset may temporarily clear the fault code, but E353 will return if the underlying cause has not been corrected. If the sensor wiring is disconnected or the sensor has failed, the control board will detect the breakaway condition again as soon as the system attempts to operate. A reset is only a useful step after completing the actual repair.