LG Refrigerator Error Code F-sensor short

The F-sensor short error on an LG refrigerator indicates a short circuit fault in the freezer compartment temperature sensor (F-sensor). The control board interprets the sensor's resistance reading as corresponding to a temperature above +50°C, which is far outside the normal operating range of a freezer. Because this reading is physically implausible under normal conditions, the board flags it as a sensor fault rather than a genuine temperature event. The F-sensor is a negative temperature coefficient (NTC) thermistor, meaning its resistance decreases as temperature rises. A short circuit causes resistance to drop abnormally low, mimicking an extreme high-temperature condition and triggering this fault code.

The most common causes involve the sensor itself or the wiring harness connecting it to the control board. Physical damage to the sensor body, moisture intrusion at the connector, or a pinched wire can all create a low-resistance short path that mimics sensor failure. In some cases, the sensor may have developed an internal short due to age or thermal stress. Because the freezer cannot reliably regulate temperature without valid sensor input, the refrigerator may enter a protective mode, potentially affecting cooling performance.

Diagnosis begins with disconnecting the F-sensor connector and measuring the sensor's resistance with a multimeter. A shorted sensor will show near-zero or very low resistance rather than the expected value for the ambient temperature. The wiring harness should also be inspected for chafing, pinched insulation, or corroded connector pins. If wiring continuity checks out and the sensor itself reads incorrectly, sensor replacement is the appropriate repair.