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Error code reference

Thermador Range Error Code Fr

Invalid door latch switch status for lower oven; communication error at display head; element supervisor disable lower oven (S/SM/SMW).

Thermador codesThermador range codes
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What the Fr error code actually means

The Fr error code means your Thermador range has detected a problem with the lower oven door latch, a communication issue between internal control boards, or a safety circuit that has shut down the lower oven. The oven may refuse to run a self-clean cycle or operate normally until the problem is resolved. A technician will need to inspect the latch mechanism, the wiring connections inside the range, and possibly the temperature sensor to find the root cause.

Diagnostic procedure

The full Fr procedure

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1
First diagnostic step
Make sure lower latch switches operating properly; replace lower latch if necessary; check all connections between power/relay boards and control head; replace lower oven temperature sensor.
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Most common causes of Fr

Ranked by how often they cause this code
  1. 1Faulty or misaligned lower oven door latch
  2. 2Failed lower oven door latch switches
  3. 3Loose or damaged wiring connections between boards and control head
  4. 4Failed lower oven temperature sensor
  5. 5Defective power board or relay board

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Questions people ask about Fr

What does Fr mean on a Thermador range?
The Fr code on a Thermador range indicates one or more issues with the lower oven: an invalid door latch switch status, a communication error at the display head, or an element supervisor circuit that has disabled the lower oven. It applies to S, SM, and SMW series models. The fault must be diagnosed and resolved before the lower oven will operate normally.
Is it safe to use my Thermador range while the Fr error is active?
The Fr code can indicate that the lower oven's element supervisor has disabled the lower cavity, which means the oven may not heat reliably or at all. Using the range for surface cooking may still be possible, but the lower oven should not be relied upon for normal cooking or a self-clean cycle until the fault is resolved. If the latch is stuck in an unknown position, avoid forcing it.
How much does it cost to repair a Thermador range showing the Fr error?
Repair costs depend on the root cause. Reseating a loose connector costs nothing beyond labor time. Replacing the lower oven door latch assembly typically falls in the range of $150 to $350 including parts and labor. A new temperature sensor is generally in the $75 to $200 range. Control board or relay board replacement is the most expensive scenario, often $250 to $600 or more depending on the specific board and labor rates in your area.
Can I fix the Fr error code myself, or do I need a technician?
Some steps are accessible to a knowledgeable DIYer, such as reseating wiring connectors between the control boards and the display head. However, testing latch switch continuity, measuring temperature sensor resistance, and diagnosing board-level faults generally require a multimeter and familiarity with appliance wiring. If you are not comfortable working inside a range, a qualified technician is the safer choice.
Will resetting the range clear the Fr error code?
Cycling power to the range by unplugging it or switching off the circuit breaker for a few minutes may temporarily clear the Fr code, but the fault will return if the underlying problem with the latch, wiring, or temperature sensor has not been corrected. A reset is useful for confirming whether a fault is intermittent, but it is not a permanent fix.

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