LG Refrigerator Error Code 16

Error code 16 on an LG refrigerator indicates a system abnormality in the defrost sensor located in the F compartment (freezer section). This sensor monitors temperature during the defrost cycle to ensure the heater activates and terminates correctly. The control board triggers error code 16 when the sensor's detected temperature falls outside the valid operating range, specifically when the reading is not lower than 122°F and not higher than -58°F. In other words, the sensor is returning a value that lands outside the expected bounds, which tells the board that the sensor circuit is not functioning reliably.

The F compartment defrost sensor is a negative temperature coefficient (NTC) thermistor, meaning its resistance changes inversely with temperature. When the sensor circuit is open due to a broken wire, the board reads an abnormally high resistance, which translates to an out-of-range temperature signal. A short circuit has the opposite effect, driving resistance toward zero and pushing the reported temperature in the other direction. Both conditions produce a signal outside the valid detection window and trigger this code. Contact failure at the connector and a missing or displaced sensor housing can produce the same intermittent or out-of-range readings.

Diagnosis should begin at the wiring harness connecting the defrost sensor to the main control board. Inspect the wire run for pinch points, chafing against cabinet edges, or rodent damage. Check the connector pins for corrosion, bent terminals, or incomplete seating. If the wiring and connector appear intact, test the sensor's resistance at room temperature to determine whether the thermistor itself has failed. A sensor reading well outside its expected resistance range at a known temperature confirms component failure.