Oven displays F4, may shut off or show erratic temperature readings

Safety first: Turn off power at the breaker. Allow the oven to cool before working.

• Remove and test sensor: Unscrew the oven sensor from the rear wall and pull it forward. Disconnect the plug and measure resistance. A reading near 0 Ω indicates a shorted sensor; replace it.
• Inspect wiring: Follow the sensor wires to the rear of the unit. Look for spots where the insulation is melted or pinched against metal. Repair damaged sections with high-temperature wire and ceramic wire nuts.
• Dry connectors: If there are signs of moisture (after steam cleaning or spillovers), dry the connector thoroughly and let the oven sit unplugged for several hours before retesting.
• Control board: If sensor and wiring are good but F4 persists, the control board input circuit may be shorted and will need replacement.