Dacor oven intermittently shows F4, often during preheat or high-temperature operation

Safety first: Turn OFF power at the breaker and allow the oven to cool before working on it.

• Inspect sensor and harness: Access the oven temperature sensor and its wiring. Wiggle the harness gently while checking for loose connections or visible damage. Secure any loose wiring away from hot surfaces and sharp edges.
• Check connectors: Disconnect and reconnect the sensor plug several times to wipe oxidation from the contacts. Ensure the locking tabs fully engage.
• Heat test (advanced): If you have a multimeter and heat source, you can gently warm the sensor (removed from oven) and watch resistance change smoothly. Any sudden jumps or open circuits indicate a failing sensor.
• Replace suspect parts: If the error occurs only at high temps, replace the sensor first. If F4 continues, inspect and possibly replace the ERC.

Because F4 is often intermittent, it may take several test cycles to confirm the repair.