LG Refrigerator Error Code F2 F3 F4 F5

These codes indicate a defrost system failure. Specifically, the defrost sensor did not detect a temperature above 41°F (5°C) after one full hour of defrosting, meaning the evaporator coils are not being cleared of frost properly. The fault typically lies with the thermal fuse (fuse-M), the defrost heater, or the defrost sensor. A damaged door gasket can also contribute by allowing excess frost to accumulate.

The refrigerator may continue to cool for a period after the code appears, but ongoing frost accumulation on the evaporator will gradually reduce airflow and cooling performance. Food safety becomes a concern if temperatures in the fresh food or freezer sections begin to rise. It is best to address the fault promptly rather than continue operating the unit in this condition.

Repair costs vary depending on which component has failed and whether the work is done by a technician or as a DIY repair. A thermal fuse is generally the least expensive part, while a complete defrost heater or sensor assembly will cost more. Professional labor adds to the total, and overall repair costs typically range from $100 to $350 depending on parts needed and local labor rates. Getting a diagnosis before ordering parts helps avoid unnecessary purchases.

Technicians and experienced DIYers can diagnose this fault using a multimeter to check three key values: fuse-M continuity (0 ohms), defrost heater resistance (48 to 54 ohms), and defrost sensor resistance (22,000 ohms or higher). Replacing any component that falls outside these specs will resolve the error if that component is the root cause. Access to the evaporator compartment is required, which involves removing freezer shelving and the evaporator cover panel.

A power reset may temporarily clear the code, but it will return once the control board runs another defrost cycle and again fails to confirm the temperature threshold was reached. The underlying component failure must be repaired to permanently resolve the error. A reset alone does not fix the defrost heater, thermal fuse, or sensor.