LG Heat Pump Error Code E501

E501 on an LG heat pump means the system has detected an outdoor temperature above 30 degrees Celsius and is blocking heating mode operation as a built-in protective restriction. This is not a component failure in itself. The code will clear and heating will resume automatically once the outdoor temperature sensor reads below the threshold. If temperatures are not actually that high, the sensor or its wiring may need to be inspected.

Yes, E501 is a protective lockout and the unit is operating safely by restricting heating mode. The system will continue to function in cooling mode or fan mode if needed. You do not need to power off the unit, and there is no risk of damage from the code itself appearing.

If the outdoor temperature is genuinely over 30 degrees Celsius, there is no repair cost at all. If the outdoor ambient temperature sensor is faulty and needs replacement, parts and labor typically range from 80 to 250 dollars depending on your location and technician rates. If the issue is traced to the main control board, that repair can range from 250 to 600 dollars or more.

If the outdoor temperature is genuinely above 30 degrees Celsius, no fix is needed since the system is protecting itself as designed. If you suspect the outdoor temperature sensor is misreading, a knowledgeable DIYer can compare the sensor reading to an independent thermometer and inspect the wiring harness for obvious damage. Replacing the outdoor ambient temperature sensor is a straightforward repair, but if the control board is suspected, a qualified technician should handle the diagnosis.

A reset may temporarily clear the E501 display, but if the outdoor temperature sensor still reads above 30 degrees Celsius, the code will return immediately when the system attempts to enter heating mode. The underlying condition, whether it is actual high outdoor temperature or a faulty sensor, must be addressed before the restriction will stay cleared.