LG OF r Error Code — What It Means
The LG “OF r” error code commonly appears on LG refrigerators to indicate an open or faulty temperature sensing circuit in the refrigerator compartment (often reported as an “Open Refrigerator sensor” or an open thermistor). When the fridge control detects an open circuit or no valid temperature reading from the refrigerator thermistor, the control board cannot regulate cooling properly and will flag the condition as OF r. This results in symptoms such as inconsistent temperatures, the compressor cycling abnormally, increased energy use, frost buildup, food spoilage risk, and in some cases, visible error on the display. While the refrigerator may continue to run, leaving the problem unfixed increases the chance of ruined food and higher electricity bills and can mask other problems like a failing defrost system or a damaged wiring harness.
Common Causes
- Faulty refrigerator thermistor (temperature sensor) — the most common root cause.
- Loose, corroded, or damaged wiring/connectors between the thermistor and main control board.
- Failed main control board (PCB) or a bad sensor input circuit on the board.
- Door switch or door-ajar condition causing improper temperature readings.
- Defrost system issues (heater or thermostat) indirectly affecting sensor readings.
- Software or firmware glitch — rare, but sometimes fixed by a power cycle or service update.
- Physical damage from ice, pests, or impact that severs sensor wires.
Troubleshooting Steps
- Safety first — unplug the refrigerator or switch off the breaker before inspecting electrical components.
- Power-cycle the unit: turn the fridge off for 5 minutes then back on. If OF r clears, monitor to see if it returns.
- Check the door seals and ensure doors close fully. An open/ajar door can cause erratic temperature readings.
- Locate the refrigerator thermistor (check owner manual or service manual for location). Visually inspect the sensor and wiring for damage, kinks, or disconnected plugs.
- Test the thermistor with a multimeter for continuity or resistance. Compare readings to the specifications found in the service manual for your model (thermistor values vary by model and temperature).
- If the thermistor shows open circuit or out-of-spec resistance, replace the sensor. Reconnect and clear codes by power cycling.
- If the thermistor reads correctly, inspect the wiring harness and connectors between the sensor and main control board for continuity and corrosion; repair or replace as needed.
- If wiring and sensor test good, test or swap the main control board only if you have the correct replacement board and technical skill — otherwise call a technician. A board-level fault on the sensor input circuit can trigger OF r.
- Check for related err