LG Heat Pump Error Code E307

E307 indicates a fault in the PWM discharge temperature sensor circuit connected to the digital compressor. The control board has detected a signal voltage above 4.95V (open circuit, corresponding to below -30°C) or below 0.5V (short circuit, corresponding to above 151°C). This error is only active when outdoor temperatures are above -10°C. The system stops normal operation to protect the compressor until the fault is resolved.

No. The E307 error means the system cannot monitor the compressor discharge temperature, which is a key safeguard against compressor overheating. Operating the unit without a functioning discharge sensor risks serious and potentially irreversible compressor damage. The unit should remain off until the sensor fault is diagnosed and repaired.

Repair costs vary depending on what is causing the fault. If only the sensor connector needs to be reseated, the cost is primarily a service call fee, typically in the range of $75 to $150. Replacing the discharge temperature sensor itself generally runs between $50 and $150 for the part plus labor. If the outdoor PCB requires replacement, costs can range from $300 to $700 or more depending on the model and labor rates in your area.

A knowledgeable DIYer can start by checking whether the discharge temperature sensor connector is fully seated on the outdoor PCB, since a loose connector is the most common cause. However, accurately measuring the sensor resistance and diagnosing wiring or PCB faults requires a multimeter and familiarity with reading circuit values. If the connector appears secure and the error persists, a qualified HVAC technician should complete the diagnosis.

A power reset may temporarily clear the error display, but if the underlying fault in the sensor, wiring, or connector is still present, E307 will return once the unit attempts normal operation. The error condition is based on a live voltage reading from the sensor circuit, so a reset alone does not resolve the root cause. The sensor and wiring must be inspected and repaired for the error to clear permanently.