LG Refrigerator Error Code Freezer Defrost Sensor Error

This error means the main PCB has detected a voltage reading outside the acceptable range of 4.5V to 1.0V on the freezer defrost sensor circuit. The defrost sensor is a thermistor that monitors freezer temperatures during defrost cycles to protect the evaporator. When this sensor or its wiring fails, the refrigerator cannot properly control defrosting and displays this code to alert the user or technician.

This error is not an immediate safety hazard, but it should be addressed promptly. If the defrost system cannot operate correctly, ice will accumulate on the evaporator coils, reducing cooling efficiency and potentially leading to food spoilage. Continued operation with this fault can also stress other refrigeration components over time.

A reset may temporarily clear the error code from the display, but if the underlying fault in the sensor circuit is still present, the code will return. Resetting does not repair a failed thermistor, damaged wiring, or faulty PCB. The error should be properly diagnosed and the root cause corrected before assuming the reset has resolved the issue.

A knowledgeable DIYer can handle some steps, such as inspecting connectors, checking wiring for visible damage, and manually defrosting the unit. However, diagnosing the fault properly requires a multimeter to check voltage at PCB connectors CN30 and CN76 and to test thermistor resistance. Replacing the thermistor is a moderately accessible repair, but if the main PCB is involved, professional service is recommended.

If the thermistor is the cause, parts typically cost in the range of $15 to $50, and a DIY repair can keep total costs low. If professional labor is involved, expect a total repair cost in the range of $100 to $250 depending on your location and the technician's rates. A main PCB replacement is considerably more expensive, often ranging from $200 to $500 or more including parts and labor.