LG Heat Pump Error Code E110

E110 indicates an error with auxiliary electric heater sensor 3. This thermistor monitors temperature within the backup electric heating assembly. The control board has detected that the sensor signal is outside its expected resistance range, prompting the fault code. The system will typically restrict or disable the auxiliary heater until the fault is cleared.

The heat pump's refrigerant-based heating circuit may continue to operate while E110 is active, but the auxiliary electric heater will be limited or disabled. This means your system may struggle to maintain setpoint temperatures in very cold weather. It is not recommended to ignore the fault long-term, as loss of auxiliary heat during extreme cold can stress the system and leave your home under-heated.

Repair costs depend on the root cause. Replacing a thermistor sensor is typically a lower-cost repair, often in the range of $75 to $250 including parts and labor if the component is accessible. If the control board requires replacement, costs can rise to the $300 to $700 range or higher depending on the specific model. A wiring harness repair or connector cleaning will generally fall at the lower end of the cost spectrum.

Some causes, such as a loose connector or a visibly damaged wire, can be addressed by a knowledgeable DIYer with basic electrical skills and a multimeter. However, the auxiliary heater assembly operates at line voltage and involves high-current components, so working inside the unit carries real electrical hazard. If you are not comfortable with electrical diagnostics on high-voltage equipment, a licensed HVAC technician should perform the repair.

A power reset may temporarily clear the code, but if the underlying sensor fault is still present, E110 will return when the system attempts to operate the auxiliary heater again. A reset is useful for confirming whether the fault is intermittent, but it does not repair a failed thermistor, damaged harness, or corroded connector. Persistent return of the code after reset confirms a physical component issue.