LG oven shows F20 and may not maintain temperature or may shut off unexpectedly.

Safety first: Disconnect power before testing components.

• Sensor resistance check: Access the oven temperature sensor at the back wall of the cavity. Disconnect and measure resistance at room temperature (~1080–1100 Ω). If out of range, replace the sensor.
• Harness inspection: Trace the sensor wires to the control board. Ensure connectors are tight and wires are not pinched or burned.
• Board evaluation: If the sensor and wiring are good, the control board's temperature circuit may be faulty. Look for burnt components or corrosion. Replace the control board if no other issues are found.
• Calibrate if available: Some LG models allow temperature calibration in the settings. After hardware repair, adjust calibration if the oven still runs slightly hot or cold.