F20 on Thermador C-Series Upper Ovens: CANCEL Key Shorted High

What F20 means

On older Thermador C-series, CM and CJ ovens, F20 means the control sees the upper oven's CANCEL key held in a high-shorted state, as if the pad were stuck. The legacy service document ties it to the display board and touch panel. Other Thermador generations may use the same F20 symbol for something unrelated, so we match it to your model first. Other keys may still respond.

Usual causes of F20

Connections between the control display board and the touch panel
Control display board, touch panel, or both, per the replacement advice

✓ A safe check worth trying

1. Dry-wipe the control panel with a soft cloth and keep anything off the glass. 2. Touch OFF, or switch the oven off at the breaker. 3. Wait three minutes, then restore power. 4. If F20 appears again, write it down and call us. Panel removal and connector checks are technician work.

! Why you should stop here

The ribbon connection behind the touch panel is delicate
Replacing the wrong half of the panel assembly is costly
You see a written price first, and the exact part is matched to your model number

Taking off a panel yourself does not by default void a manufacturer warranty, yet it can lead to accidental damage, and some manufacturers attach their own service terms. Read your warranty paperwork, or ask us, before you decide.

→Same appliance

More Oven codes

F12F12 on a Legacy Thermador C-Series Oven: Vcc Lift-Off on the Power/Relay Board F51F51 on an Older Thermador Wall Oven (C/CM-Series): Upper Door Stuck Unlocked F2F2 on an Older Thermador Wall Oven (SC, SCD, SM, SMW): Temperature or Door Light During Self-Clean F13Thermador C/CM/CJ Wall Oven Code F13: Power Board Not Calibrated, Air Switch Check F52Thermador Wall Oven F52 in the Legacy C/CM Family: Upper Door Reads Locked and Open F3Thermador Wall Oven F3 in the Legacy SC/SM Family: Open Oven Sensor F14Thermador Older C-Series Oven, Control Display EEPROM Error F14 F53What F53 Means on a Legacy Thermador C/CM Wall Oven: Upper Door Stuck Locked

F20F20 questions

Does F20 affect only the upper oven?

The code names the upper oven's CANCEL key. F21 covers the lower oven's equivalent. On a single-cavity model, tell us which oven you have so we match the wording correctly.

What does shorted high mean?

The control sees a voltage level as though the key were being pressed. It could come from the pad, the ribbon connection or the board, which is why the source lists several parts.

Can moisture cause F20?

Water or cleaner on the panel can confuse touch keys. Wiping it dry and resetting is a reasonable single step. If the code persists once the panel is dry, the hardware needs a look.