What this code means
The F7 (or F-7) error code on an LG electric range indicates a heating-performance fault. According to LG support documentation, this code appears when the oven temperature did not exceed 150°F for five minutes or longer during preheat while the door was closed. LG also lists F7 as an upper convection fan error on its range error-code pages.
The fault can be triggered by multiple causes in the heating path: a failed or obstructed upper convection fan, a faulty oven temperature sensor (thermistor), a broken bake or broil element, damaged wiring between components, or a failed relay control board that is not delivering power to the heating elements. In some cases, low supply voltage can also prevent proper heating, though that requires an electrician to diagnose.
Before You Replace Anything
Many owners replace the main control board first, but the fan, sensor, or elements are far more likely. Always test the convection fan for mechanical failure, check the temperature sensor resistance against the model’s specification table, and verify element continuity before condemning the control board.
Common Causes
- Upper convection fan failure or obstruction The fan assembly may have seized, become obstructed by debris, or lost electrical continuity, preventing the control from detecting proper airflow and heating performance.
- Oven temperature sensor (thermistor) fault A sensor that reads out of range or open will prevent the control from seeing the oven temperature rise, triggering the F7 code even if the elements are heating.
- Failed bake or broil element An open or high-resistance element cannot heat the cavity to the threshold temperature within the required time, causing the control to abort preheat.
- Damaged wiring or connectors Burnt spade terminals, loose plugs, or broken conductors between the elements, sensor, and control board interrupt power or feedback signals.
- Relay control board or main control board failure When the fan, sensor, and elements test good but the oven still will not heat, the relay board may not be switching power to the heating circuit.
Step-by-Step Fix
- Press CLEAR/OFF and turn off the range at the circuit breaker for at least 30 seconds to reset the control board, then restore power and attempt a new preheat cycle.
- Confirm the symptom by starting a preheat cycle with the door closed and using an oven thermometer to verify the cavity does not reach 150°F within five minutes.
- Inspect the upper convection fan for mechanical seizure, obstructions, or damage. Disconnect power, remove the fan cover (usually inside the oven cavity or on the rear wall), and spin the fan blade by hand. Test the fan motor windings for continuity with a multimeter.
- Test the oven temperature sensor by disconnecting it from the wiring harness and measuring its resistance at room temperature. Compare the reading to the resistance table in your model’s service manual or wiring diagram.
- Check bake and broil element continuity by removing each element’s wire leads and measuring resistance across the terminals. A working element will show a low resistance (typically 15 to 50 ohms, depending on wattage). An open element will read infinite resistance.
- Inspect all wiring and connectors between the elements, temperature sensor, convection fan, and the relay or main control board. Look for burnt spade terminals, melted insulation, or loose plugs. Repair or replace damaged harnesses.
- Test the relay control board output if the fan, sensor, and elements all pass testing. Verify the board is sending voltage to the fan and element terminals during preheat. Replace the relay or main control board only after confirming all other components are functional.
Parts Often Needed
| Part | Notes |
|---|---|
| LG range upper convection fan assembly | Amazon | Verify the part number matches your exact LG range model. Fan assemblies are model-specific. |
| LG range oven temperature sensor (thermistor) | Amazon | Also called an oven sensor probe. Confirm compatibility with your model number before ordering. |
| LG range bake or broil element | Amazon | Measure the failed element’s resistance and compare to the service manual to confirm the correct wattage replacement. |
| LG range relay control board or main control board | Amazon | Only replace after all other components pass testing. Control boards are the most expensive part and the least likely cause of F7. |
When to Call a Pro
Call a professional appliance technician if you are uncomfortable working with 240-volt circuits, if the fault persists after resetting and basic inspection, or if you do not have a multimeter and the service manual needed to test sensor resistance and element continuity. A qualified technician can safely diagnose the convection fan motor, verify relay board switching, and trace intermittent wiring faults that are difficult to find without specialized test equipment. If low voltage is suspected (the oven heats weakly or cycles on and off), contact a licensed electrician to measure the supply voltage at the breaker and outlet before replacing any range components.