LG Refrigerator Error Code rD

The rD code indicates a problem with the refrigerator compartment defrost sensor located on the evaporator. When the display also shows 'Lo', the sensor circuit is open, meaning the sensor or its wiring is disconnected. When it shows 'Hi', the circuit is shorted. Both conditions prevent the control board from monitoring the evaporator temperature correctly during defrost cycles.

Resetting the refrigerator by unplugging it or cycling the power may temporarily clear the display, but the rD code will return if the underlying sensor fault has not been corrected. The main PCB will re-detect the open or short circuit in the RD-sensor loop as soon as it runs its diagnostic checks. A permanent fix requires repairing or replacing the sensor or its wiring.

Repair costs vary depending on whether the issue is a simple connector reseating, a wiring repair, or a full sensor replacement. A replacement RD-sensor part typically costs in the range of $20 to $60 depending on the specific model. If a technician is hired for diagnosis and replacement, total costs including labor generally fall in the range of $100 to $250. Main PCB replacement, if ever required, would be significantly more expensive.

A knowledgeable DIYer can start by checking the wiring harness running from the evaporator sensor to connector CN15 on the main PCB, looking for visible damage or a loose connection. However, properly diagnosing this code requires a multimeter to measure sensor resistance after disconnecting CN15. If the sensor itself has failed, replacing it on the evaporator requires disassembly of the refrigerator compartment interior panels, which is more involved and may be better suited to a technician.

Operating the refrigerator with an active rD fault is not recommended for extended periods. Without a functioning defrost sensor, the control board cannot accurately manage defrost cycles, which can lead to heavy frost accumulation on the evaporator coil. Over time, this frost buildup will restrict airflow and cause the refrigerator to lose cooling efficiency, potentially leading to food spoilage.