Thermador C-Series Upper Oven, Sensor Shorted: F30 on C271 to CJ302 Models

What F30 means

F30 on an older Thermador C, CM or CJ oven says the upper oven sensor circuit is shorted, so the control no longer gets a sane temperature reading and stops heating. The legacy service document describes a short in the sensor wiring and gives a resistance of about 1080 ohms at room temperature for a healthy sensor. Newer Thermador ovens may use F30 differently.

Usual causes of F30

Short circuit in the upper oven sensor wiring or connections at header P3 on the power/relay board
Sensor wire pinched
Sensor out of range, or the power/relay board if the sensor tests fine

✓ A safe check worth trying

1. Touch OFF, or turn the oven off at its breaker. 2. Let the cavity cool completely before anyone reaches in. 3. Wait three minutes and restore power. 4. If F30 returns, leave the upper oven off and call us. Measuring the sensor and inspecting header P3 are technician steps.

! Why you should stop here

A good sensor reads about 1080 ohms cold, which only a meter shows
A pinched wire can look fine until the oven is pulled out
We quote in writing first, with legacy parts confirmed by model number

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

F12F12 on a Legacy Thermador C-Series Oven: Vcc Lift-Off on the Power/Relay Board F51F51 on an Older Thermador Wall Oven (C/CM-Series): Upper Door Stuck Unlocked F2F2 on an Older Thermador Wall Oven (SC, SCD, SM, SMW): Temperature or Door Light During Self-Clean F13Thermador C/CM/CJ Wall Oven Code F13: Power Board Not Calibrated, Air Switch Check F52Thermador Wall Oven F52 in the Legacy C/CM Family: Upper Door Reads Locked and Open F3Thermador Wall Oven F3 in the Legacy SC/SM Family: Open Oven Sensor F14Thermador Older C-Series Oven, Control Display EEPROM Error F14 F53What F53 Means on a Legacy Thermador C/CM Wall Oven: Upper Door Stuck Locked

F30F30 questions

What does 1080 ohms tell you?

It is the expected sensor resistance at room temperature. Our technician measures it with the oven cold. A reading far off points at the sensor or its wiring, while a good one points at the board.

Is it safe to use the lower oven?

The code names the upper sensor, so the lower cavity may still work. We recommend avoiding use until the control is inspected, since both ovens share the same board.

Could the wire be pinched during installation?

Yes, the source specifically mentions checking that the sensor wire is not pinched. It can also be damaged later by moving the oven, which is why we inspect the whole run.