The oven displays F4; the temperature reading is erratic or the oven shuts off with an error.

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

• Inspect sensor and wiring: Access the oven temperature sensor from inside the cavity or rear panel. Look for melted insulation, bare wires touching metal, or burnt connectors.
• Test resistance: Disconnect the sensor and measure resistance. A reading near 0 Ω indicates a shorted sensor; replace it.
• Check for shorts to ground: With the sensor disconnected, measure resistance from each sensor lead to the oven chassis. Any low resistance indicates a short in the harness; repair or replace the harness.
• Dry connectors: If there is evidence of moisture (from spills or steam), dry the area thoroughly and clean the connector with electrical contact cleaner.
• Control board: If the sensor and wiring are good but F4 persists, the electronic oven control board may have an internal short and should be replaced.