LG Heat Pump Error Code P523

P523 indicates that the outdoor unit's second Electronic Expansion Valve (EEV 2) failed its self-diagnosis close test. The unit commanded the valve to fully close and detected that the valve did not respond correctly. This points to a problem with the EEV 2 assembly, its wiring harness, or the outdoor control board. The system will not operate normally until the fault is resolved.

Operating the unit with an active P523 code is not advisable. An EEV that cannot close properly disrupts refrigerant flow control, which can lead to compressor damage, system flooding, or further component failures. It is best to shut the unit down and contact a qualified technician promptly to prevent additional and potentially more costly damage.

Repair costs vary depending on the failed component. Wiring harness repairs or connector replacements tend to be on the lower end of the cost range, typically in the range of $100 to $250 including labor. EEV replacement costs generally fall between $250 and $600 depending on parts and labor rates in your area. If the outdoor control board is at fault, parts and labor can bring the total to $400 to $900 or more. A diagnostic visit fee will usually apply regardless of the repair outcome.

Most of the repairs involved with a P523 code require working with refrigerant lines and internal electrical components of the outdoor unit, which is not recommended for untrained individuals. A technician can perform coil resistance checks on the EEV and inspect the wiring harness, which are the most common starting points. If the valve or control board needs replacement, professional service is required. Attempting repairs without proper tools and refrigerant handling certification can be unsafe and may void warranties.

A power reset may temporarily clear the error code, but it will return if the underlying fault with EEV 2 has not been corrected. The code is generated by a self-diagnosis routine that runs during operation, so any unresolved mechanical or electrical issue with the valve will trigger P523 again. A reset alone is not a fix and should not substitute for proper diagnosis.