LG Heat Pump Error Code E102

E102 indicates that the indoor unit's room temperature sensor has an open or short circuit fault. The control board cannot read a valid resistance value from the NTC thermistor that monitors ambient room temperature. The system stops normal operation until the sensor circuit is restored to a valid state. Diagnosing this code starts with measuring the sensor's resistance and comparing it to the expected values for the current room temperature.

The heat pump will generally not operate normally while E102 is active, since the system requires a valid room temperature reading to control heating or cooling output. Attempting to force operation without a functioning room sensor risks improper temperature control. It is best to leave the unit off until the sensor fault is resolved.

A power reset may temporarily clear the displayed code, but E102 will return as soon as the PCB re-reads the faulty sensor circuit. The error will continue to appear until the underlying open or short circuit in the sensor, wiring, or connector is physically corrected. Resetting without repairing is not a lasting solution.

Some causes of E102 are DIY-accessible, such as reseating a loose connector or replacing the room temperature sensor thermistor. The sensor is typically clipped into the indoor unit's air inlet area and connects to the PCB with a small plug. However, if the fault lies in the wiring harness or the PCB itself, the repair is more involved and may be better handled by a qualified technician.

If only the room temperature sensor needs replacement, parts typically cost between $10 and $40, and the job is relatively straightforward. If the indoor PCB is at fault, board replacement can range from $150 to $400 or more depending on the model. Adding professional labor will increase the total cost, generally ranging from $100 to $300 for a service call.