LG Heat Pump Error Code E231

E231 indicates a PWM discharge temperature sensor error on your LG heat pump outdoor unit. The control board has detected a sensor signal voltage above 4.95V or below 0.5V, which correspond to temperature readings outside the valid range of -30°C to 151°C. This fault is only registered when the outdoor ambient temperature is above -10°C. The system shuts down or restricts operation to protect the compressor until the fault is resolved.

It is not advisable to continue operating the heat pump while E231 is active. The discharge temperature sensor protects the compressor from overheating, and without a valid sensor signal, the control system cannot monitor that critical parameter. Running the unit under these conditions risks compressor damage, which is a much costlier repair than fixing the sensor fault.

Repair costs vary depending on what is causing the fault. If the issue is simply a loose connector, a service call fee of roughly $80 to $150 may be all that is needed. A replacement discharge temperature sensor typically adds $20 to $80 in parts plus labor. If a wiring harness or control board replacement is required, total repair costs can range from $200 to $600 or more depending on parts availability and labor rates in your area.

A knowledgeable DIYer can start by inspecting the sensor connector on the outdoor unit for loose pins, corrosion, or visible wiring damage, and reseating the connector. However, accurate diagnosis requires measuring sensor resistance with a multimeter and comparing it to a resistance-temperature reference table, which is work better suited to a technician. If the sensor or control board needs replacement, a certified HVAC technician should handle those repairs, particularly because refrigerant system checks may also be needed.

A power reset may temporarily clear the error code, but if the underlying sensor, connector, or wiring issue is still present, E231 will return once the unit restarts and the control board detects the out-of-range signal again. A reset is useful for confirming whether the fault is intermittent, but it does not constitute a repair and should not be used as a substitute for proper diagnosis.