Thermador Oven Error Code F61

The F61 error code on a Thermador oven indicates that the lower oven temperature sensor circuit has opened, meaning the control system is detecting an infinite or out-of-range resistance reading from the sensor. Temperature sensors in Thermador ovens are typically resistance-based RTD (resistance temperature detector) components whose resistance changes predictably with temperature. When the circuit goes open, the control board receives no valid resistance reading and immediately flags the F61 fault to prevent uncontrolled heating conditions.

The first diagnostic step is to inspect the sensor wiring at pin header P2 on the relay board. A broken wire, corroded connector, or pin that has backed out of the header will sever the electrical path and trigger the fault just as readily as a failed sensor itself. The wiring harness runs from the lower oven cavity sensor through the oven chassis to the relay board, and any point along that path is a potential failure site, especially near the oven cavity opening where heat cycling can degrade insulation and connections over time.

If the wiring and connector at P2 check out visually and with a continuity test, the lower oven sensor itself is likely the culprit. An open sensor produces no resistance reading, which is outside the normal operating range the control expects. The sensor should be tested with a multimeter at the sensor leads to confirm whether it is open. Replacement of the sensor or repair of the wiring harness is the typical resolution for this fault code.