F4
AGA
Temperature Sensor Short / Out-of-Range Low Resistance
AGA oven shows F4 and may shut down mid-cycle; temperature control is erratic.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Sensor internal short, moisture ingress into sensor, wiring shorted together, control PCB misinterpretation of sensor signal
How to Fix / Troubleshooting
Safety first: Disconnect the oven from mains power before testing.
- Visual inspection: Remove the sensor from the cavity and inspect the sheath for cracks, moisture, or corrosion at the tip.
- Resistance test: At room temperature, measure resistance across the sensor. Compare to AGA specifications; a very low reading (near 0 Ω) or no change when warmed indicates a shorted sensor.
- Check harness for shorts: With the sensor unplugged, test between each harness conductor and chassis ground. Any continuity suggests a short to earth that must be corrected.
- Drying moisture: If the sensor appears wet (after steam cleaning, for example), allow it to dry fully and retest. Persistent F4 after drying means replacement is required.
- Replace sensor or PCB: Fit a new AGA-compatible temperature sensor if readings are incorrect. If the new sensor does not resolve F4, the control PCB may be faulty.
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Repair Difficulty
Medium
3/5
Required Part
Oven Temperature Sensor Probe (AGA NTC)
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