Thermador · Oven / Range
E121 Pro Recommended Thermador Oven E121 — Control Board Communication Error
Part of the control panel stops responding and some cooking modes disappear.
What does Thermador E121 mean?
The main oven control unit lost communication with a secondary board (e.g. the user interface or the relay board). Multiple cooking functions may become unresponsive.
What causes Thermador E121?
- Loose ribbon cable between control boards
- Power surge affecting one or both boards
- Failed control board
How to fix Thermador E121 yourself
- 1 Turn off the oven at the circuit breaker for 2 minutes, then restore — power cycling clears most transient communication faults.
- 2 If the display shows E121 immediately after power restore, it is a persistent hardware fault.