AGA range displays F4 and oven will not start or shuts down shortly after starting

Safety first: Disconnect power at the mains before any disassembly.

• Inspect sensor and wiring: From inside the oven, locate the sensor probe and ensure it is not crushed or touching metal parts that could short it. From the rear, inspect the sensor harness for pinched or melted insulation.
• Resistance test: Unplug the sensor from the harness and measure resistance. A reading near 0 Ω indicates a shorted sensor. Replace the sensor if shorted.
• Check connector for moisture: Look for condensation or spills that may have reached the sensor connector. Dry thoroughly and reseat the connector.
• If sensor is normal: The short may be on the control board. Inspect the board for burnt tracks or components around the sensor input. Board replacement is usually required if damage is found.

When to call a technician: If you cannot access the rear panel safely or are unsure about electrical testing, contact an AGA service engineer.