Bosch Range F12: Control Module Cannot Recognize Its Own Processor

What F12 means

A range that refuses to start and shows F12 has a control module that could not recognize its own microprocessor (older Bosch Evolution models). The service manual files this next to the checksum alarm as one of two internal board errors, and observes that power surges, voltage swings and other supply trouble can set off either, so a worn board is not the only suspect.

Common causes of F12

Internal board failure
Surge or voltage swing
Problem with the supply to the range circuit

✓ One safe check you can try

1. Take the range off power at the breaker for thirty seconds, which is the procedure the manual itself gives. 2. Restore power and read the display. 3. If F12 appears again right away, the manual says the board is defective and must be replaced. 4. Stop resetting at that point.

! Why to stop there

Repeated resets on a damaged board accomplish nothing and keep stressing it.
If the supply caused the damage, a new board can suffer the same fate unless the supply is checked.
This board governs oven and surface safety, so a guessed repair is a poor gamble.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Range codes

F91Bosch Range F91 Means the Unlock Attempts Ran Out F92Bosch Range F92: Oven Believes the Door Is Open F93Bosch Range F93 Is the Lock-Side Twin of F90 F94Bosch Range F94: Door Lock Attempts Exhausted F10Bosch Range F10 on the Evolution Platform: Runaway Heat Alert F11Bosch Range F11 Can Be as Simple as a Pressed Key F13Bosch Range F13 Signals Corrupted Stored Settings F30Bosch Range F30: Reading 1080 to 1110 Ohms on the Oven Sensor

F12F12 questions

Should my house wiring be examined?

It is worth ruling out. The manual lists surges and line voltage swings among the causes, and a circuit that damaged one board can damage the next one too.

How does F12 differ from F13?

Both are internal board errors with the same diagnosis and the same remedy; they differ only in which internal check came up short on this older range.

Does repair make sense on this older model?

Usually, when the rest of the range is sound, although board supply for this generation is not guaranteed. We give a written price before replacing anything.