Thermador Range Error Code F112

The F112 error code on a Thermador range indicates a runaway temperature condition in the lower oven, meaning the oven's internal temperature has exceeded 650°F without the control system commanding or acknowledging that level of heat. This is a protective fault triggered when the Power Board detects that the lower oven sensor is reporting temperatures beyond the safe operating threshold. Rather than a simple overheating event, a runaway condition typically points to a control or sensing failure where the oven cannot regulate heat properly, either because the heating element is receiving power it should not be, or because the temperature feedback loop has broken down.

The lower oven temperature sensor plays a central role in diagnosing this fault. At room temperature, the sensor should read approximately 1080 ohms of resistance. A reading significantly outside this value indicates a failed sensor that may be reporting incorrect temperatures to the Power Board, causing the board to misinterpret the oven's actual state. The P24 connector on the Power Board is the first physical checkpoint, as a loose or corroded connection at this point can disrupt sensor signal integrity and produce false runaway readings.

If the sensor resistance measures correctly and the P24 connector is secure, the Power Board itself is the likely cause and should be replaced. Additionally, the wiring between the Power Board and the lower heating element should be inspected, since a shorted or damaged wire could allow the element to energize uncontrollably, producing a true thermal runaway condition rather than a sensor or board reporting error.