Thermador Range Error Code F4

F4 indicates a shorted oven temperature sensor or, on S, SM, and SMW series models, a sensor reading corresponding to a temperature below 40 degrees Fahrenheit. On ESC30 and GSC30 models, F4 is exclusively a shorted sensor fault. The sensor should measure approximately 1050 ohms at room temperature when checked at the Molex connector on the main power and relay board. A reading significantly lower than this points to a defective sensor or shorted wiring.

No, you should not attempt to use the oven while F4 is active. The error indicates the control board cannot accurately monitor oven temperature, which means the oven may not regulate heat correctly. Continuing to operate it under these conditions could create a safety risk or cause further damage to the control system.

Resetting the range by cutting power at the breaker or unplugging it may temporarily clear the F4 code, but the error will return as soon as the control board re-reads the shorted sensor circuit. A reset does not address the underlying fault. The sensor resistance and wiring must be tested and the defective component repaired or replaced to resolve the code permanently.

A knowledgeable DIYer can begin by checking the sensor wiring harness for visible damage and measuring the sensor resistance at the Molex connector on the relay board using a multimeter. If the sensor reads well below 1050 ohms at room temperature, the sensor probe will need to be replaced. Wiring repairs and control board connector inspection are also within reach for those comfortable working on appliances, but working near the relay board requires the range to be fully unplugged first.

If only the oven temperature sensor needs replacement, parts typically range from around 30 to 80 dollars depending on the model, with professional labor adding another 100 to 200 dollars. If the fault lies in the wiring harness or the main relay board itself, total repair costs can be higher, often in the 200 to 500 dollar range including parts and labor. Getting a firm diagnosis before ordering parts will help avoid unnecessary expenses.