Thermador Oven Error Code F30

The F30 error code on a Thermador oven indicates that the upper oven temperature sensor has developed a short circuit. The oven temperature sensor is a resistance-based probe (typically an RTD or NTC thermistor) that the control board reads continuously to monitor cavity temperature. When a short occurs in the sensor or its wiring, the resistance value drops abnormally low, outside the expected operating range. The control board interprets this as an invalid signal and triggers the F30 fault to prevent unsafe operation.

The first diagnostic step is to inspect the sensor wiring at pin header P3 on the relay board. A short can occur at several points: within the sensor probe itself, along the wire harness running from the sensor to the relay board, or at the connector seated in P3. Corrosion, pinched wiring, or heat damage along the harness can all create a low-resistance path that mimics a shorted sensor. Measuring resistance across the sensor leads while disconnected from the board will confirm whether the sensor itself has failed or whether the fault lies in the wiring.

If the sensor reads near zero ohms or well below its rated resistance at room temperature, the probe has internally shorted and must be replaced. If the sensor reads correctly when isolated but the fault persists when reconnected, the wiring harness or the P3 connector on the relay board should be closely inspected for damage, melted insulation, or a bridged connector pin. Resolving the fault requires eliminating the short completely before the control board will resume normal operation.