What this code means
LG uses the F3 error code for two different faults depending on the model family. On LG’s official range error-code list, F3 indicates a touch-pad sensor key error, meaning the control has detected a stuck or shorted key input on the touch panel. On LG’s parts and service documentation for other range models, F3 means the oven temperature sensor (thermistor) is shorted for more than one minute during cooking. LG’s own support video describes F3 as an open oven sensor condition that should clear after a power reset, and if it returns the unit requires repair.
Because LG assigns the same code to both keypad faults and oven sensor faults across different model families, the first step is to confirm your exact model number and check whether the fault occurred during touch-panel interaction or during oven operation. If the code appeared while using the touch controls, suspect the keypad or control membrane. If it appeared during cooking or heating, suspect the oven sensor circuit. Both paths share a common troubleshooting start: power-cycle the range and inspect the affected area for obvious signs of contamination or damage.
Before You Replace Anything
Many owners replace the main control board when F3 appears, but the fault is often a dirty or shorted touch panel or a failed oven sensor. Clean the panel and test the sensor resistance before ordering the board.
Common Causes
- Moisture, grease, or foreign material on the touch panel Spills, steam, or food residue can bridge contacts on the touch membrane and hold a key input active long enough to trigger a key-error fault.
- Failed oven temperature sensor or thermistor A shorted or open thermistor sends an abnormal signal to the control, and the board logs F3 if the condition persists for more than one minute during cooking.
- Stuck or shorted keypad membrane Age, heat, and repeated use can degrade the touch-panel membrane so that one or more keys remain electrically closed even when not pressed.
- Wiring harness or connector fault Loose, corroded, or damaged connectors between the touch panel, oven sensor, and main control board can mimic a sensor short or key fault.
- Defective main control board If the touchpad and sensor circuits both check good, the control board itself may be misreading the inputs or failing to clear the fault after reset.
Step-by-Step Fix
- Press Clear or Off on the control panel, then shut off the circuit breaker or unplug the range from the wall outlet.
- Wait one to two minutes to allow the control board to fully discharge and clear any temporary fault memory.
- Restore power and observe whether F3 reappears immediately or only during use. If the code does not return, monitor the range for a few cycles before taking further action.
- Inspect the touch panel if the code returns. Wipe the entire control surface with a soft damp cloth to remove grease, moisture, or food residue, then dry it thoroughly.
- Check the oven sensor and its wiring if your model documents F3 as a sensor fault. Pull the range forward, remove the rear access panel, and inspect the sensor connector at the back of the oven cavity for corrosion, loose pins, or damaged wires.
- Measure the oven sensor resistance if you have a multimeter and your model’s service literature. Disconnect the sensor, measure across its two terminals, and compare the reading to the specification in your wiring diagram. Field references often cite around 1080 to 1100 ohms at room temperature, but verify against your model’s data before using that value as a pass or fail threshold.
- Replace the failed component if the fault persists after cleaning, resetting, and testing. Install a new touch panel, oven sensor, wiring harness, or main control board depending on which part tested faulty, following the installation instructions in your service manual.
Parts Often Needed
| Part | Notes |
|---|---|
| LG range touch panel or keypad assembly | Amazon | Match the part number on your existing panel or look up by model number on LG’s parts site. |
| LG oven temperature sensor or thermistor | Amazon | Usually a two-wire probe mounted in the rear wall of the oven cavity. Confirm the connector style before ordering. |
| LG range main control board or PCB | Amazon | Only replace after confirming the touchpad and sensor circuits both test good. The board is the most expensive part in the repair path. |
When to Call a Pro
Call a professional if you are uncomfortable working inside the range cabinet, if the sensor resistance measurement does not match published specifications and you are unsure how to interpret the reading, or if both the touchpad and sensor test good but the code persists. A technician can verify the control board with specialized diagnostics and source the correct replacement parts by model number. Also call for service if the range uses 240-volt wiring and you are not confident isolating and reconnecting high-voltage circuits safely, or if the fault returns repeatedly after you have replaced the sensor or touchpad and you suspect a board-level failure.