LG Refrigerator Error Code FZ-Sensor Error

The FZ-Sensor Error means the refrigerator has detected a fault in the freezer compartment temperature sensor circuit. The error is triggered when the sensor signal falls outside the valid voltage range of 1.0V to 4.5V at the main PCB, or when the reported temperature exceeds 149°F (65°C) or drops below -58°F (-50°C). Possible causes include a failed sensor, a wiring disconnection, a short circuit, or a corroded connector.

It is not advisable to continue using the freezer normally while this error is active. Without a reliable temperature reading, the refrigerator control board cannot properly regulate freezer temperature, which means food in the freezer may not be kept at a safe temperature. Monitor freezer temperatures manually with a thermometer and minimize door openings until the fault is repaired.

A reset may temporarily clear the error code from the display, but it will return if the underlying hardware fault is not corrected. If the sensor is failed, the wiring is damaged, or a connector is loose, the control board will detect the same out-of-range signal and re-trigger the error after the reset. Clearing the code is only a useful step as part of a diagnostic process, not as a standalone fix.

Some causes of this error are DIY-accessible. Start by checking that the sensor connector is fully seated at both the sensor end and at the main PCB connectors CN30-3 and CN76-1. If you have a multimeter, you can measure the voltage across those connectors and test sensor resistance to determine whether the sensor or the wiring is at fault. Replacing the sensor is a moderate-difficulty repair, but main PCB replacement is generally best left to a technician.

Repair cost depends on the root cause. A replacement freezer temperature sensor typically costs between $15 and $50 for the part alone. If the main PCB is at fault, parts can range from $100 to $300 or more depending on the model. Adding labor for a professional technician, total repair costs generally fall between $80 and $400.