Thermador Range Error Code F31

F31 indicates that the upper oven temperature sensor circuit is reading as open, meaning the control board cannot detect a valid signal from the RTD sensor. The oven will not heat while this fault is active because the control has no way to regulate temperature safely. The sensor should read approximately 1080 ohms at room temperature when functioning correctly. The fault can originate at the sensor itself, the wiring, the header connections on the power and relay board, or the board itself.

The range displays F31 specifically because it cannot monitor oven temperature, which means it cannot prevent overheating. Using the oven in this condition is not safe and the oven heating function is typically disabled by the control when this fault is active. Surface burners on a gas or electric range may still operate, but the oven should not be used until the fault is resolved.

Resetting the range by disconnecting power for a few minutes may temporarily clear the F31 code, but the error will return if the underlying fault is still present. The control will detect the open sensor circuit again as soon as it attempts to read oven temperature. A reset is useful for confirming the fault is persistent rather than a one-time glitch, but it does not substitute for diagnosing and repairing the faulty sensor, wiring, or board.

A knowledgeable DIYer can perform the initial diagnostics by checking connector seating and measuring the sensor resistance with a multimeter. If the sensor resistance is far from 1080 ohms at room temperature, the sensor is a straightforward part to replace. However, inspecting solder joints at headers P3 and P4 or replacing the power and relay board involves working with internal board components, which is better suited to a technician with appliance repair experience.

Repair costs vary depending on which component has failed. A replacement oven temperature sensor typically costs in the range of $25 to $75 for the part alone. If the power and relay board requires replacement, parts can range from $150 to $400 or more depending on the specific model. Adding professional labor will increase the total, generally bringing a full repair to somewhere between $150 and $600 depending on the fault and your location.