F12 on the older Thermador C271, C272, C301, C302, CM301, CM302 and CJ302 ovens refers to a Vcc lift-off, a drop in the supply voltage the power/relay board gives to its own logic. The code stops…
F12 on the older Thermador C271, C272, C301, C302, CM301, CM302 and CJ302 ovens refers to a Vcc lift-off, a drop in the supply voltage the power/relay board gives to its own logic. The code stops normal operation until a technician steps in. The service document gives a single action, replacing the power/relay board, and other Thermador generations may print F12 with another meaning.
1. Reset once: touch OFF or turn the oven off at the circuit breaker, then wait three minutes before turning it back on. 2. If F12 appears again, note the number and call us for an inspection. Nothing inside the oven or behind the panel is meant for owners to touch.
It is the small DC supply that powers the board's logic circuits. When it lifts off, the board cannot run reliably, so the control stops and shows F12 instead of guessing.
The table names a single action, replacing the power/relay board. We still test first, because a board is a significant cost on an older oven and you deserve a confirmed diagnosis.
It might clear the display once. If F12 returns, the board is the focus. The manual's three-minute reset is a fair first step, but not a repair.
Our technician checks it in your home and hands you a written price before touching anything.