LG Refrigerator Error Code R4 R5

The R4 and R5 codes indicate a defrost system malfunction. The refrigerator's control board detected that the defrost sensor did not rise above 50°F (10°C) within 2 hours of the defrost cycle starting. This points to a problem with one or more components in the defrost system, including the thermal fuse, defrost heater, defrost relay, or the drain.

The refrigerator may continue to cool for a period of time after this code appears, but ice will gradually build up on the evaporator coils and reduce airflow. Over time, this will cause the unit to lose cooling efficiency and could result in food spoilage. It is best to address the defrost system issue promptly rather than continuing to operate the refrigerator with this fault active.

Repair costs depend on which component has failed. A thermal fuse is one of the least expensive parts, typically in the range of $5 to $25 for the part alone. A defrost heater replacement may cost $20 to $80 in parts. If the control board or relay requires replacement, costs can rise to $100 to $300 or more for parts. Adding a professional labor charge of $100 to $200 is typical if you are not doing the repair yourself.

Some causes of this error are DIY-friendly. Clearing a clogged or frozen defrost drain can often be done without special tools. Testing the thermal fuse and defrost heater for continuity requires a multimeter but is a straightforward process for someone comfortable working with appliances. Replacing a blown thermal fuse or burned-out heater is a common repair, though relay or control board issues may benefit from a professional technician.

A reset may temporarily clear the error code display, but the underlying defrost system fault will remain. The code will return once the refrigerator runs through its next defrost cycle and the sensor again fails to reach 50°F within 2 hours. A reset should only be used as part of diagnosis, not as a long-term solution.