LG Air Conditioner Error Code 103

Error code 103 indicates that the discharge temperature of the No. 2 constant speed compressor in the Sub2 outdoor unit has exceeded its safe operating limit in a three-unit system. The compressor has been shut down automatically to prevent internal damage. A technician should check the service valve status on that outdoor unit as the first diagnostic step before investigating refrigerant charge and heat exchanger condition.

No. The system has already shut down the affected compressor as a protective measure. Attempting to override or restart the unit repeatedly without resolving the root cause can cause permanent damage to the compressor internals, including valve failure and motor winding burnout. Leave the system off and contact a qualified technician for diagnosis.

Repair cost depends heavily on the root cause. If the fix is simply opening a service valve, the cost is primarily a service call fee, typically in the range of $75 to $150. Refrigerant leak repair and recharge can range from $200 to $600 or more depending on the refrigerant type and leak location. Compressor replacement on a commercial multi-zone system is a major repair that can range from $800 to $2,500 or higher including labor and parts.

The first step, checking whether the service valve on the outdoor unit is fully open, can be done without special tools and may resolve the fault if the valve was inadvertently left closed after prior service. However, if the valve is open, diagnosing the underlying cause requires refrigerant manifold gauges, sensor resistance testing, and potentially handling refrigerant, all of which require certified HVAC technician qualifications. Attempting refrigerant work without proper certification is illegal in most jurisdictions.

A power reset may temporarily clear the fault and allow the compressor to restart, but if the underlying condition causing high discharge temperature has not been corrected, the error will return and the compressor will shut down again. Repeated fault cycles without repair can progressively damage the compressor. A reset should only be performed after the root cause has been identified and corrected.