Thermador Oven Error Code F23

The F23 error code on a Thermador oven indicates that the lower oven cancel key has been detected in a shorted-low condition. This means the control board is reading a continuous low-voltage signal from the cancel key input on the lower oven's keypad membrane or touchpad assembly, as if the key is being constantly pressed. The control interprets this as a stuck or shorted switch, which prevents normal operation since a perpetually active cancel signal would interfere with cooking cycles and safety logic.

The cancel key is part of the control panel's touchpad membrane, which sends discrete electrical signals to the electronic control board when keys are pressed. In a normal state, the cancel key circuit rests at a defined voltage level and drops low only momentarily when pressed. A shorted-low condition means that circuit is being pulled low continuously, either due to physical damage to the membrane, contamination such as moisture or food debris bridging the contacts, or a failure within the ribbon cable connecting the touchpad to the control board.

This fault can also originate at the electronic control board itself, where the input circuit for the cancel key may have failed internally. However, keypad membrane failures are far more common than board-level failures in this specific scenario. Because the cancel key is continuously signaling the board, the oven will typically lock out cooking functions until the fault is resolved and cleared.