Thermador Wall Oven F3 in the Legacy SC/SM Family: Open Oven Sensor

What F3 means

When F3 flashes on an older Thermador SC, SCD, SM or SMW oven, the control sees an open oven sensor: the circuit is broken or the plug has worked loose. With no temperature reading, the oven will not run. The service document gives the sensor a target of about 1050 ohms at room temperature and asks that the sensor plug be fully seated.

Usual causes of F3

Open sensor or open circuit in the sensor wiring
Sensor plug at the molex connector not fully seated
Sensor that does not measure about 1050 ohms at room temperature

✓ A safe check worth trying

1. Stop using the oven until the cavity has cooled. 2. Turn power off at the breaker for 3 minutes, then back on. 3. If F3 flashes again, jot down the code and the model number. 4. Do not reach behind the oven to push plugs. Call us.

! Why you should stop here

Plug access is behind panels on a built-in oven
Open circuits need resistance testing, not eyeballing
A loose plug can look like a failed sensor

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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More Oven codes

F11Thermador CM/CJ Built-In Oven F11 (Legacy C-Series): Power Board Communication Error F40Thermador Oven F40 on Older C-Series Models: Upper Meat Probe Shorted F84Thermador Wall Oven F84 on Legacy C/CM-Series Ovens: Lower Latch Input Shorted F12F12 on a Legacy Thermador C-Series Oven: Vcc Lift-Off on the Power/Relay Board F50Older C/CM-Series Thermador Wall Oven F50: Upper Door Signal Shorted Low F1Older SC/SM-Series Thermador Wall Oven F1: Element Supervisor Enabled F13Thermador C/CM/CJ Wall Oven Code F13: Power Board Not Calibrated, Air Switch Check F51F51 on an Older Thermador Wall Oven (C/CM-Series): Upper Door Stuck Unlocked

F3F3 questions

What does open mean here?

Open means the electrical loop through the sensor is broken. The control reads no signal at all, so it cannot tell the oven temperature and refuses to heat.

Could it just be a loose plug?

Possibly. The source asks to confirm the sensor plug is seated, but the plug sits behind the oven, so that check is ours. We would rather confirm than promise from a table.

Does F3 mean a new oven?

Not on its own. A sensor or connection fix is the usual route, and we quote it in writing before any work. Only the parts that test bad go on the quote.