LG Fridge RT Error Code

As an expert technician, I have diagnosed the LG fridge with an error code RT This specific code indicates a failure in the Room Temperature Sensor (Ambient Sensor) circuit. This sensor monitors the temperature of the air surrounding the refrigerator, allowing the main control board to adjust cooling cycles and defrost timing based on external conditions. When the board detects a short circuit or an open circuit in this path, it triggers the RT display.

LG Fridge RT Error Code: Troubleshooting Steps

1. Power Reset: Disconnect the refrigerator from the power source for 5 minutes. Plug it back in to see if the code clears. If the code returns immediately, proceed to physical inspection.
2. Locate the Sensor: The room temperature sensor is typically located on top of the refrigerator, housed under a small plastic vented cover near the door hinge or the top-front edge of the cabinet.
3. Inspect Wiring: Remove the screw holding the sensor cover. Inspect the wire harness for any signs of corrosion, pinched wires, or loose connections. Ensure the connector is firmly seated.
4. Resistance Testing: Disconnect the Room Temperature Sensor from the wire harness. Use a multimeter set to the Ohms (Ω) setting to test the sensor’s resistance.

Expected Ohmic/Resistance Values

The room temperature sensor is a thermistor, meaning its resistance changes based on the temperature. At standard room temperatures, you should see the following values:

• At 68°F (20°C): Approximately 11.5kΩ to 12.5kΩ
• At 77°F (25°C): Approximately 10kΩ
• At 86°F (30°C): Approximately 8kΩ to 8.5kΩ

If the multimeter reads 0 Ω “short circuit” or OL “open circuit/infinite resistance,” the room temperature sensor is defective and must be replaced.

Estimated Repair Cost

• Replacement Sensor: $20 – $55 USD.
• Main Control Board (only if the sensor and wiring are confirmed good): $120 – $250 USD.

Repair Difficulty

DIY (Easy): Replacing the room temperature sensor is a straightforward task that requires only a Phillips head screwdriver and a multimeter for verification. Most homeowners can complete this repair in under 20 minutes. If the issue is determined to be the main control board, the difficulty remains moderate, as it involves unplugging and replugging wire harnesses on the back of the unit.