LG Heat Pump Error Code E271

E271 indicates a sump temperature sensor error, meaning the oil temperature sensor in the outdoor unit is sending a signal outside the valid range. The fault is detected when the outdoor temperature is above -10 degrees Celsius and the sensor voltage is above 4.95V (open circuit) or below 0.5V (short circuit). This is a protective lockout to prevent compressor damage from operating with an unreliable oil temperature reading.

No, you should not attempt to bypass or ignore the E271 error and continue operating the unit. The oil temperature sensor protects the compressor from running outside safe temperature limits. Operating the compressor without a functioning oil temperature sensor risks compressor damage, which is one of the most costly repairs on a heat pump.

Repair costs vary depending on the root cause. If the fix is simply reseating a connector or repairing a wiring fault, labor costs may range from around 75 to 150 dollars. If the oil temperature sensor itself requires replacement, parts and labor combined typically range from 150 to 350 dollars. Control board replacement, if needed, is significantly more expensive and can range from 400 to 800 dollars or higher depending on the model.

Start by checking the oil temperature sensor connector on the outdoor unit for looseness, corrosion, or damage and reseat it securely. Next, measure the resistance of the sensor itself and verify it is within the expected range for the ambient temperature. If the sensor reads open or shorted, it will need to be replaced. If the connector and sensor are both good, inspect the wiring harness between the sensor and the control board for damage.

A power reset may temporarily clear the fault display, but if the underlying sensor or wiring problem is still present, the E271 code will return once the unit attempts to operate with the outdoor temperature above -10 degrees Celsius. A reset alone does not fix the fault and is not a substitute for diagnosing and repairing the sensor circuit.