Safety first: Turn off power at the breaker before inspection.

Visual inspection: Check the sensor inside the oven for damage or signs of overheating. From the rear, inspect the sensor wiring for melted insulation or contact with metal surfaces.
Disconnect and test sensor: With a multimeter, measure resistance across the sensor terminals at room temperature. A very low reading (near 0 Ω) indicates a shorted sensor that must be replaced.
Check for moisture: Look for moisture or corrosion in the sensor connector. Dry and clean with isopropyl alcohol if needed, then reconnect firmly.
Inspect harness routing: Ensure the sensor wires are not pinched under panels or touching sharp metal edges. Reroute or insulate as needed.
If sensor and wiring are normal: The main PCB may be misreading the sensor due to an internal fault and may need replacement.

Warning: Do not operate the oven with known wiring shorts; this can cause further damage or shock risk.

Oven displays F4 and may shut off heating; can appear intermittently during long baking cycles.

Possible Causes