LG Refrigerator Error Code R-DEFROST SENSOR ERROR

The R-DEFROST SENSOR ERROR means the Main PCB has detected a problem with the refrigerator compartment defrost sensor circuit. The board monitors voltage between pins 6 and 8 of connector CN30, and a reading outside the 1.0V to 4.5V range triggers this fault. The cause can be a loose or corroded connector, a dislodged sensor, a broken wire, a wiring short, or a sensor that has failed internally.

Short-term use is generally possible, but the defrost cycle may be suspended while the error is active, which means frost can accumulate on the evaporator coil over time. Heavy frost buildup will eventually block airflow and cause the refrigerator to lose cooling capacity. It is best to diagnose and address the fault promptly to prevent food spoilage or damage to other components.

A power reset may temporarily clear the error code from the display, but the fault will return if the underlying problem has not been fixed. The Main PCB continuously monitors the voltage at CN30 pins 6 and 8, so any sensor, wiring, or connector issue will cause the error to reappear. A reset is useful for confirming whether the fault is intermittent, but it is not a substitute for proper diagnosis and repair.

Some causes are DIY-friendly. Reseating the sensor into its evaporator mounting clip or reconnecting a loose harness plug requires no special tools. Checking the voltage at CN30 pins 6 and 8 with a multimeter is also straightforward. Replacing the defrost sensor or repairing a damaged wiring harness is within reach for someone comfortable working with basic appliance wiring, but if the Main PCB itself is faulty, professional service is recommended.

If the fix is simply reseating the sensor or reconnecting a loose plug, there is no parts cost. A replacement defrost sensor typically costs in the range of $15 to $60 for the part alone. If a technician is needed, total repair costs including labor generally range from $100 to $250, depending on local rates and whether additional components such as the wiring harness or Main PCB need to be replaced.