LG Heat Pump Error Code G3

The G3 code means the outdoor unit COND MID sensor has become disconnected or has lost its signal to the control board. COND MID refers to a thermistor that monitors the mid-point temperature of the condenser coil. The system generates this fault to prevent unsafe operation without accurate coil temperature data. Reconnecting or replacing the sensor is required to clear the fault.

It is not recommended to continue operating the system while the G3 fault is active. The COND MID sensor provides critical coil temperature data that the control board uses to protect the compressor and manage refrigerant flow. Running the system without this data could result in compressor damage or reduced system life. Address the fault before resuming normal operation.

If the repair only involves reseating a loose sensor or connector, the cost is primarily a diagnostic service call, typically in the range of $75 to $150 depending on your area. If the sensor itself needs replacement, parts and labor together generally range from $100 to $300. More extensive wiring harness repairs or control board issues could increase the total cost beyond that range.

If you are comfortable working around the outdoor unit, you can open the access panel and visually check whether the sensor has pulled free from its mounting clip or connector. Reseating a loose connector or clipping the sensor back into its bracket may resolve the issue. If the sensor wire is damaged or the thermistor has failed, replacement is required and a qualified technician should handle the repair.

A power reset may temporarily clear the fault code, but the G3 error will return if the underlying sensor connection issue is not corrected. The control board will detect the missing or invalid sensor signal as soon as the system restarts. A permanent fix requires physically inspecting, reconnecting, or replacing the COND MID sensor.