LG Heat Pump Error Code P522

P522 is a self-diagnosis error indicating that Electronic Expansion Valve 1 (EEV1) in the outdoor unit failed to complete its close operation during the system's internal check routine. The control board commands the valve to fully close, and when the expected response is not confirmed, the error is triggered. This code causes the unit to halt normal heating or cooling operation to prevent refrigerant flow issues.

It is not recommended to attempt to force the unit to operate with P522 active. An EEV that cannot properly close can lead to uncontrolled refrigerant flow, which may cause compressor flooding or other refrigerant circuit damage. The system's shutdown response to this code is a protective measure and should be respected until the fault is resolved.

A power cycle reset may temporarily clear the error code and allow the unit to restart, but if the underlying fault with EEV1 is still present, the code will return during the next self-diagnosis cycle. A reset is useful for confirming whether the fault is intermittent, but it does not repair the hardware issue. Persistent return of P522 after a reset confirms that a component-level diagnosis and repair is required.

Basic checks such as inspecting the EEV wiring harness connectors and looking for obvious damage can be done without specialized tools. However, measuring EEV coil resistance, diagnosing the outdoor PCB driver circuit, and handling refrigerant system components all require proper equipment and, in the case of refrigerant work, EPA certification. Most repairs beyond a connector reseating will need a qualified HVAC technician.

Repair costs vary depending on the root cause. If only a wiring harness repair or connector replacement is needed, costs are typically in the range of $100 to $250 including labor. An EEV replacement can range from $200 to $600 or more depending on parts and labor rates. Outdoor control board replacement tends to be at the higher end of the cost range, often $300 to $700 or more.