LG Refrigerator Error Code Fridge 2nd Digit f

The 'f' error in the second digit position of an LG refrigerator's display indicates a CoolSelect Zone sensor fault. The CoolSelect Zone is a dedicated compartment within the refrigerator that allows the user to select specific temperature modes for storing meats, beverages, or other items. The sensor responsible for monitoring this zone's temperature has either lost its connection to the main control board or is returning readings outside the acceptable range, specifically temperatures at or above +50°C or at or below -50°C. These out-of-range readings signal that the sensor is no longer providing valid data to the control system.

The fault can originate from several physical or electrical conditions. A connector may have slipped out of its socket on either the sensor side or the main PCB side, an internal wire in the harness may be cut or pinched, the circuit may have developed an open contact through corrosion or mechanical stress, or the sensor itself may have short-circuited. Any of these conditions will cause the control board to register abnormal thermistor resistance, which translates into the extreme temperature readings that trigger this error code.

Diagnosing this fault begins at the main PCB connector CN30. Measuring voltage between pins 4 and 6 on that connector should yield a reading within the 4.5V to 1.0V range under normal operating conditions. A reading outside this window confirms an electrical fault in the sensor circuit, while a reading within range points toward a marginal or intermittent connection. From there, the technician should inspect the wiring harness for physical damage and test the sensor's thermistor resistance directly to isolate whether the sensor itself or the wiring is the root cause.