Older SC/SM-Series Thermador Wall Oven FC: Display Head Communication Error

What FC means

FC flashes on older Thermador SC, SCD, SM and SMW ovens when the display head detects a communication error. The two halves of the control are not talking, which often means the second power/relay board in a double oven is not powering up. The service document lists a replacement order, but we confirm which part has failed by testing the cables first.

Usual causes of FC

Second power/relay board that is not powering up
Cables or harnesses between the main and second power/relay boards and the control head
Display head, after the second board
Main power/relay board, last in the replacement order

✓ A safe check worth trying

1. Touch OFF or switch the oven off at the breaker. 2. Wait 3 minutes before restoring power. 3. If FC remains, write down the code and your model number. 4. Do not unplug any harness. Call us. Keep the door closed and children away while you wait.

! Why you should stop here

The service document replaces parts in a set order, so testing saves money
Harness checks need access behind the control head
Several boards share the link and must be tested together

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.

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FCFC questions

What is the display head?

It is the control unit with the screen and touch panel. FC says it lost contact with the boards that run the oven. Nothing is repaired until the cause is understood.

Why does a second board matter?

Double ovens add a second power/relay board for the other cavity. If it fails to power up, the display head cannot complete its conversation, which gives FC.

Is FC the same as F-?

They are related but different. FC is a communication error seen by the display head, while F- is one seen by the main power/relay board.