LG Heat Pump Error Code E222

E222 indicates an outdoor ambient temperature sensor breakaway fault. The system has detected an open circuit or lost signal from the thermistor that measures outside air temperature. The heat pump shuts down because it cannot safely manage defrost cycles or heating calculations without this input. A technician will need to inspect the sensor, its wiring, and connector in the outdoor unit.

No, the system will typically not operate while this fault is active, and attempting to force operation without a functioning outdoor temperature sensor is not advisable. Without accurate ambient temperature data, the system cannot properly time defrost cycles or manage refrigerant pressures, which could lead to compressor damage. Address the fault before returning the unit to normal operation.

A power reset may temporarily clear the code and allow the unit to restart, but if the underlying wiring or sensor fault remains, the E222 error will return quickly. A reset is useful for confirming whether the fault is intermittent or persistent, but it is not a repair. The sensor circuit needs to be diagnosed and corrected for the system to operate reliably without the code recurring.

Some basic checks are within reach for a knowledgeable DIYer, such as visually inspecting the outdoor unit for disconnected wiring connectors or obvious wire damage. However, safely accessing the outdoor control board and testing thermistor resistance requires familiarity with heat pump components and a multimeter. If the sensor or wiring needs replacement, a qualified HVAC technician is recommended to ensure the repair is done correctly.

Repair costs vary depending on the root cause. If only a connector needs cleaning or reseating, a service call fee of roughly $75 to $150 may be all that is required. A replacement outdoor ambient temperature sensor typically costs between $15 and $60 for the part, plus labor. If the outdoor control board has failed, total repair costs including parts and labor can range from $300 to $700 or more.