LG Heat Pump Error Code P756

P756 is a self-diagnosis error indicating that Electronic Expansion Valve number 3 (EEV3) in the outdoor unit failed to close correctly during the system's startup check. The heat pump monitors this valve's response and shuts down when it does not complete the closing cycle as expected. This error points to a problem with the valve itself, its coil, the connecting wiring, or the outdoor control board.

No. The P756 error means the system has detected that a critical refrigerant flow control valve is not operating correctly, and the heat pump will typically shut itself down to prevent compressor damage or refrigerant circuit problems. Attempting to override or repeatedly restart the unit without addressing the fault can cause additional damage.

A power reset may temporarily clear the error code and allow the unit to restart, but if the underlying fault with EEV3 is still present, the P756 error will return during the next self-diagnosis cycle. A reset is useful for confirming whether the fault is intermittent, but it is not a repair. The root cause must be identified and corrected to resolve the error permanently.

Some preliminary checks, such as inspecting the wiring harness and connectors at the outdoor unit for obvious damage or corrosion, can be performed by a knowledgeable DIYer. However, testing coil resistance, diagnosing the control board, or replacing the EEV requires refrigeration and electrical knowledge along with proper tools. Most homeowners should contact a qualified HVAC technician for this repair.

Repair costs vary depending on the failed component. Replacing an EEV coil or harness is typically less expensive, often in the range of $150 to $400 including labor. Replacing the full EEV valve assembly or the outdoor control board can cost anywhere from $400 to $900 or more depending on parts availability and local labor rates.