An upper-oven F31 on the Thermador C271, C272, C301, C302, CM301, CM302 or CJ302 group reports that the temperature sensor circuit is open, as though the wire were broken or a joint had let go. Without…
An upper-oven F31 on the Thermador C271, C272, C301, C302, CM301, CM302 or CJ302 group reports that the temperature sensor circuit is open, as though the wire were broken or a joint had let go. Without a reading the control will not heat. The service table checks connections and a sensor resistance of about 1080 ohms, then solder joints at header P3 on the power/relay board.
1. Switch the oven off using OFF or the breaker and let it cool. 2. Wait three minutes before restoring power. 3. Try the lower oven if you have one. 4. If F31 comes back on the upper oven, call us and keep it off. Do not unplug or probe the sensor yourself.
F30 is a short circuit in the sensor wiring, while F31 is an open circuit. Both use the same expected sensor resistance, but they send the technician to different problems in the wiring or joints.
It is the connector area on the power/relay board where the upper oven sensor wiring lands. Solder joints there can crack with years of heat cycles, which is why the source calls them out.
We would rather you did not. The sensor is not the only suspect, and replacing it without testing may leave F31 on screen. We test first and quote in writing.
Our technician checks it in your home and hands you a written price before touching anything.