LG Heat Pump Error Code E273

E273 on an LG heat pump signals a fault with the SUMP TEMP FIXED 2 sensor, which monitors the oil temperature in the outdoor unit compressor sump. The error is triggered when the sensor voltage goes above 4.95V or below 0.5V, indicating an open or short circuit condition. This error is only active when outdoor temperatures are above -10°C. The system shuts down to protect the compressor from running without reliable oil temperature data.

No, you should not continue operating the heat pump while E273 is active. The compressor oil temperature sensor is a protective component, and running the system without accurate oil temperature monitoring risks compressor damage. The unit typically shuts down automatically when this error is detected, and it should remain off until the fault is diagnosed and repaired.

A power reset may temporarily clear the E273 error from the display, but the code will return if the underlying sensor fault is still present. Because the error is tied to a measurable voltage condition, the control board will detect the out-of-range signal again as soon as the system restarts and the outdoor temperature is above -10°C. A lasting fix requires diagnosing and repairing the sensor, connector, or wiring issue rather than relying on resets.

Some aspects of diagnosing E273 are accessible to a knowledgeable DIYer, such as checking that the sensor connector is fully seated and inspecting wiring for visible damage. However, measuring sensor resistance accurately and replacing components in the outdoor unit requires basic electrical testing skills and familiarity with heat pump systems. If the sensor itself or the control board needs replacement, it is recommended to have a qualified technician handle the repair to avoid further damage.

Repair costs depend on the root cause. If only the connector needs cleaning or reseating, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the oil temperature sensor needs replacement, parts and labor combined generally fall in the range of $150 to $350. A control board replacement is more expensive, often ranging from $400 to $800 or more depending on the unit model and labor rates in your area.