LG Refrigerator Error Code Er 4

Er 4 indicates an abnormal defrost sensor condition caused by a short circuit in the defrost heater, a blown thermal fuse, or a disconnected wiring connector in the defrost circuit. The code does not appear immediately; it displays approximately 4 hours after the fault is first detected by the control board. This error means the defrost system is not functioning correctly and requires inspection.

A refrigerator displaying Er 4 has a non-functional defrost system, which means frost will continue to accumulate on the evaporator coils. Over time, this will restrict airflow and cause the refrigerator to lose cooling ability. While the appliance may continue running in the short term, leaving the fault unrepaired risks food spoilage and potential compressor strain. Addressing the error promptly is recommended.

Repair costs vary depending on which component has failed. A thermal fuse is typically an inexpensive part, often in the range of $5 to $20, while a defrost heater assembly can cost $20 to $80 or more depending on the model. If you hire a technician, labor charges will add to the total, generally bringing the full repair cost to somewhere between $100 and $300 depending on your location and the specific parts needed.

Some causes of Er 4, such as a loose or unplugged wiring connector, can be resolved without replacing any parts if you are comfortable working inside the freezer compartment. However, replacing a blown thermal fuse or a failed defrost heater requires purchasing the correct replacement component and basic skills with a multimeter for continuity and resistance testing. If you are not comfortable with electrical testing, a qualified appliance repair technician should perform the diagnosis.

A power reset may temporarily clear the Er 4 display, but the code will return within approximately 4 hours if the underlying fault in the defrost circuit has not been corrected. Because the error is tied to a hardware fault such as a blown fuse, a failed heater, or a loose connector, resetting alone does not constitute a repair. The root cause must be identified and corrected.