LG HVAC Error Code CH02

CH02 on an LG HVAC system means the outdoor thermistor has detected an open or short circuit condition. The outdoor thermistor is a temperature sensor in the outdoor unit that the control board uses to monitor ambient conditions. When the sensor signal falls outside the expected range, the system shuts off operation and displays CH02 to alert you to the fault.

No. The system is designed to turn off when CH02 is triggered, and attempting to force operation without a functioning outdoor thermistor removes a key monitoring input from the control system. Operating without proper temperature sensing could allow refrigerant pressures to reach unsafe levels. It is best to leave the system off and resolve the fault before resuming use.

If the fix is simply reseating a loose connector, the cost is limited to a service call fee, typically in the range of $75 to $150 depending on your area. If the outdoor thermistor itself needs replacement, parts are generally inexpensive, and the total repair including labor usually falls in the $100 to $300 range. Control board replacement, if required, is the most costly scenario and can range from $300 to $600 or more depending on the specific unit.

A knowledgeable homeowner can safely inspect and reseat the outdoor unit's electrical connectors, which resolves CH02 in many cases. However, if the thermistor itself needs to be tested with a multimeter or replaced, or if the wiring harness is damaged, having an HVAC technician perform the repair is recommended. Working inside the outdoor unit requires care around capacitors, which can hold a dangerous electrical charge even when the unit is off.

A power reset may temporarily clear the code and allow the system to restart, but if the underlying fault in the thermistor or its wiring has not been corrected, CH02 will return quickly once the control board re-evaluates the sensor signal. A reset is useful as a final step after completing repairs to confirm the fault is resolved, but it is not a substitute for diagnosing and fixing the root cause.