LG Air Conditioner Error Code 175

Error code 175 means the system has detected a failure in the Sub1 constant speed compressor 2 operation. The code can be triggered by three conditions: mechanical compressor locking, check valve leakage in the refrigerant circuit, or dielectric breakdown of the compressor motor windings. This error applies to LG multi-compressor systems and requires hands-on diagnostic testing to identify the specific root cause.

You should not attempt to continue operating the system with error code 175 active. Dielectric breakdown in a compressor poses an electrical safety risk, and a mechanically locked compressor can draw excessive current and cause additional component damage. The system controller typically disables the affected compressor circuit for this reason, so continued operation attempts may worsen the underlying fault.

A power reset may temporarily clear the error code from the display, but the underlying mechanical or electrical fault will remain. If the compressor is locked, has dielectric breakdown, or the check valve is leaking, the error will return as soon as the system attempts to run that compressor again. Resetting without repair is not a solution and could mask the fault while allowing further damage to occur.

The diagnostics and repairs required for error code 175 are not suitable for most homeowners. Checking a magnetic contactor, measuring insulation resistance with a megohmmeter, and evaluating refrigerant circuit check valves all require specialized tools and technical knowledge. Additionally, any work involving refrigerant circuits legally requires EPA Section 608 certification in the United States. A qualified HVAC technician should perform the diagnosis and repair.

Repair costs vary significantly depending on the root cause. If the issue is a failed check valve or magnetic contactor, costs are typically in the range of $150 to $500 including parts and labor. Compressor replacement in a commercial or multi-compressor LG system is considerably more expensive, often ranging from $800 to $2,500 or more depending on the unit and refrigerant recovery requirements. A technician will need to diagnose the specific cause before providing an accurate estimate.