Reviewed by Simon Kagan · 35+ years experience · CA License #51112
Error Code Er rt
The Er rt code means the room temperature sensor has failed or is sending readings outside its normal range. This sensor measures the ambient temperature around the refrigerator. The main board uses this reading to adjust compressor run time, defrost intervals, and fan speeds based on the room conditions. A failed sensor causes the board to use incorrect assumptions, leading to overcooling, undercooling, or excessive energy use.
Common Causes
Failed room temperature thermistor: The thermistor element breaks internally. The board reads OL (open) or 0 ohms (shorted) instead of a valid temperature-dependent resistance value.
Sensor exposed to direct heat: The room sensor is mounted near the condenser area or behind the kickplate grille. Heat from the condenser coils or a nearby heat vent pushes the sensor reading beyond its expected range.
Corroded or loose connector: The sensor connector corrodes from humidity or vibrates loose. An intermittent connection creates erratic readings.
Damaged wiring: The sensor wires run along the base of the refrigerator where they get pinched by the kickplate or chewed by pests.
DIY Troubleshooting
Reset the refrigerator: Unplug the unit for 5 minutes. Plug it back in. If Er rt clears and stays clear for 24 hours, a temporary spike in room temperature or a wiring glitch caused the false alarm.
Locate the room temperature sensor: The room temperature sensor is typically mounted behind the front kickplate grille at the bottom of the refrigerator or near the main control board at the rear. Remove the kickplate (pull it forward or release the clips). The sensor is a small thermistor with two wires.
Check for heat sources: Make sure no heating vent, dishwasher exhaust, or oven is blowing hot air directly onto the sensor location. Reposition the refrigerator if necessary to keep the sensor area at true room temperature.
Test the thermistor: Disconnect the sensor harness. Set a multimeter to the 20K-ohm range. At room temperature (around 77 degrees F), a typical LG room sensor reads approximately 5,000 ohms. OL (open) or 0 ohms means the sensor has failed. Replace it.
Inspect and repair wiring: Trace the sensor wires to the main board connector. Look for gnaw marks, pinch points where the kickplate sits, or connector corrosion. Repair damaged wires with butt connectors and heat-shrink tubing.
Parts You May Need
If you're handling this repair yourself, you'll need the correct OEM part for your specific model.
AppliancePartsPros.com — our supplier of choice. Same-day shipping on in-stock orders. 365-day return policy.
Professional Repair
Room sensor replacement is a quick repair, but if the sensor reads correctly and Er rt persists, the main control board's input circuit needs testing. TruePro's $59 diagnostic is credited toward the repair. All work carries a 90-day warranty on parts and labor. CA License #51112. Same-day service is often available in LA County, Orange County, and Ventura County. Call 877-378-3111. First-time customers save 15% on labor with code NEW15.
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FAQ
What does LG error code Er rt mean?
LG error code Er rt means the room temperature sensor has failed or is sending readings outside its normal range.
Can I fix error code Er rt myself?
Yes, in many cases. Follow the step-by-step troubleshooting guide above — start with a power reset, then work through the checks. The most common fix is replacing the ambient thermistor, which is within DIY range. If the code returns after basic troubleshooting, you'll need a professional. Free diagnostic with approved repair.
How much does it cost to fix error Er rt?
Typical repair costs: DIY: $15 - $40 | Pro: $130 - $240. Free diagnostic with approved repair.
Estimated Cost
DIY: $15 - $40 | Pro: $130 - $240
Free diagnostic with approved repair
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