LG Range F6 Error Code - Causes & Fix

LG Range F6 Error Code — What It Means

The F6 error code on an LG range indicates an upper oven heating error, specifically a thermistor fault in the temperature sensing system. The thermistor is a temperature sensor that tells the control board how hot the upper oven cavity is. When the control board detects a reading outside the normal range, a wiring problem, or no signal at all from the sensor, it throws F6 and may shut down upper oven operation to prevent unsafe heating.

LG’s official documentation describes this as a thermistor error and notes that the unit may require service if the code returns after a reset. The fault is localized to the upper oven heating and sensing circuit, not a general communication or keypad problem.

Jump to Fix

Common Causes

• Failed or out-of-range thermistor The upper oven temperature sensor itself has drifted out of spec, failed open, or shorted, so the control board reads an impossible temperature value.
• Loose or corroded thermistor connector The plug at the thermistor or control board has backed out, corroded, or developed a poor connection that mimics a sensor failure.
• Damaged wiring harness Wires in the upper oven sensor circuit are pinched, burned, or broken, creating an open or short circuit that triggers the heating error.
• Intermittent sensor circuit Vibration or heat cycling causes the thermistor leads or connector to make and break contact, so the code appears sporadically.
• Control board fault Less commonly, the control board’s thermistor input circuit fails and misreads a good sensor, typically only after sensor and wiring checks pass.

Step-by-Step Fix

1. Write down your exact model number from the label inside the oven door or on the back of the range, because LG error codes and thermistor specs vary by product family.
2. Power-cycle the range by turning it off at the control panel, switching off the dedicated circuit breaker for at least 30 seconds, then restoring power and checking if F6 clears.
3. Locate the upper oven thermistor, usually a small metal probe mounted through the rear or side wall of the upper oven cavity with two wires leading to a connector behind the back panel.
4. Inspect the thermistor connector and harness for backing out, corrosion, burn marks, or pinched wires, and reseat any loose plugs firmly.
5. Test the thermistor resistance at room temperature using a multimeter (consult your model’s service manual for the exact resistance table, as LG does not publish generic values) and check harness continuity to the control board.
6. Replace the upper oven thermistor if resistance is out of spec, the circuit is open or shorted, or the sensor shows physical damage, using the correct part number for your model.
7. Arrange service for the control board only if the thermistor circuit tests good, the code persists after reset, and you have verified all connections, as LG recommends professional service for persistent thermistor errors.

Parts Often Needed

When to Call a Pro

Call a qualified appliance technician if the F6 code returns immediately after a power reset, if you are not comfortable working inside a 240-volt range cabinet, or if the thermistor and wiring both test within spec but the fault persists. LG’s guidance states that persistent thermistor errors require service rather than guesswork part swaps. A technician has access to the model-specific resistance tables, wiring diagrams, and control-board diagnostics needed to pinpoint whether the fault is in the sensor circuit or the control system itself. Because the upper oven shares high-voltage components with the rest of the range, any work beyond a simple reset or visual connector check carries shock risk and should be left to someone trained and insured for that work.