LG Refrigerator Error Code E 5

E 5 on an LG RSG5B* series refrigerator indicates an open or short circuit in the fridge compartment defrost sensor. The main PCB monitors the defrost sensor circuit and triggers this code when the signal voltage at connector CN30 pins 10 and 9 falls outside the expected 1.0V to 4.5V range. The defrost sensor is a thermistor that helps the refrigerator determine when to end a defrost cycle, so a fault here can impact cooling performance over time.

The refrigerator may continue to run in a limited capacity, but operating it with a defective defrost sensor carries risks. Without a working defrost sensor, ice can accumulate on the evaporator coil, which will restrict airflow and eventually cause the fridge compartment to lose cooling ability. Food safety could be compromised if temperatures rise, so the issue should be diagnosed and repaired promptly.

A power reset may temporarily clear the E 5 code from the display, but the error will return if the underlying fault in the defrost sensor circuit has not been corrected. Resetting does not repair a failed thermistor, damaged wiring, or corroded connector. The code should be treated as an active diagnostic indicator requiring inspection and repair rather than a one-time alert that can be dismissed.

A knowledgeable DIYer can start by inspecting the wiring harness and connectors associated with the defrost sensor for visible damage, corrosion, or loose connections, as these can sometimes be corrected without replacing parts. If the sensor itself has failed, replacing the defrost thermistor is a moderate-difficulty repair that involves accessing the evaporator area. Voltage testing at CN30 pins 10 and 9 on the main PCB requires a multimeter and some comfort working with electronics.

If the defrost sensor is the cause, the part itself typically costs between $15 and $50 depending on the supplier, making it a relatively affordable repair if done yourself. Professional repair service, including labor, generally runs between $100 and $250 for a sensor replacement. If the main PCB is the faulty component, costs increase significantly, often ranging from $200 to $450 or more including parts and labor.