Bosch Oven F31 Error Code — What It Means
The F31 error code on a Bosch oven signals that the control board has detected an abnormal signal from the oven temperature sensor circuit. The control thinks the temperature sensor (RTD probe) is shorted, open, or reading values that are outside the expected range. This can be caused by a failed sensor, damaged wiring between the sensor and the control board, a loose or corroded connector, or a faulty input on the control board itself.
The oven will typically shut down or refuse to heat until the fault is cleared. The error is not usually caused by the oven getting too hot, but rather by the control losing reliable communication with the sensor that monitors cavity temperature.
Common Causes
- Failed oven temperature sensor (RTD probe) The sensor develops an internal short or open circuit, or its resistance drifts out of specification so the control rejects the signal.
- Damaged or shorted sensor wiring harness Wires between the sensor and control board are melted, pinched, rubbed through, or shorted together or to the chassis.
- Loose or corroded sensor connector The plug at the sensor or the control board becomes loose, corroded, or heat-damaged, breaking electrical contact.
- Faulty control board input circuit If the sensor and harness test correctly, the control board’s temperature-sensor input circuit has failed and cannot process the signal.
Step-by-Step Fix
- Power-cycle the oven by switching off the circuit breaker for two minutes, then restore power and check if the F31 code returns.
- Inspect the temperature sensor and wiring visually for heat damage, pinched or melted insulation, burned connector terminals, or loose plugs at the sensor and control board.
- Measure the sensor resistance by unplugging the sensor connector and testing across the two sensor leads with a multimeter (one Bosch troubleshooting reference lists about 1,080 ohms at room temperature as a field target, but consult your model’s service data for the exact specification).
- Check for a short to ground by measuring resistance from each sensor lead to the oven chassis with the sensor disconnected (you should see infinite resistance on both leads).
- Replace the oven temperature sensor if it reads open, shorted, or outside the expected resistance range for room temperature.
- Repair or replace the wiring harness if the sensor tests good at the probe but the resistance is wrong at the control board connector, or if you find visible wire damage.
- Replace the electronic control board if the sensor and harness both test correctly and all connections are clean and tight, yet the F31 code persists after power-cycling.
Parts Often Needed
| Part | Notes |
|---|---|
| Oven temperature sensor / RTD probe | Amazon | Match the sensor by your Bosch model number. The probe mounts inside the oven cavity, usually at the upper rear wall. |
| Sensor wiring harness | Amazon | Order the harness if wires are melted, cut, or shorted and cannot be repaired with heat-shrink splices. |
| Electronic control board (ERC / main control) | Amazon | Required only if sensor and wiring test good but the fault remains. Verify the board part number before ordering. |
When to Call a Pro
Call a qualified appliance technician if you are not comfortable working inside a live electrical appliance, if you do not own a multimeter or are unsure how to measure resistance and test for shorts, or if you have replaced the sensor and inspected the wiring but the F31 code continues to appear. A technician can perform the full diagnostic sequence, verify that the new sensor is reading correctly at the control board, and determine whether the control board input circuit has failed. If your oven is still under warranty, contact Bosch or an authorized service provider before opening the unit.