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Error code reference

Bosch Range Error Code F31

Oven temperature sensor failure (open) when cook or clean is programmed; fault limit 20 seconds to avoid…

Bosch codesBosch range codes

Oven temperature sensor failure (open) when cook or clean is programmed; fault limit 20 seconds to avoid erroneous faults due to line noise on long sensor wires.

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What F31 means on a Bosch range

The F31 error code on a Bosch range indicates that the oven temperature sensor has been detected in an open circuit condition while a cook or clean cycle is active. The oven temperature sensor, also called an RTD (resistance temperature detector) or NTC sensor, continuously reports oven cavity temperature to the control board by varying its electrical resistance. When the circuit is broken or resistance goes out of the expected range, the control board can no longer receive valid temperature data and triggers F31 to halt operation and prevent an uncontrolled heating condition.

Bosch designed a 20-second fault limit before F31 is triggered to prevent false errors caused by line noise on the sensor wiring. Because sensor wires can run considerable lengths through the oven chassis, they are susceptible to electromagnetic interference that can momentarily disrupt the signal. This built-in delay ensures the fault is a genuine, sustained open circuit rather than a transient spike. If the open condition persists beyond 20 seconds during cooking or self-cleaning, the code is confirmed and the oven shuts down the heating circuit.

The most common causes include a physically broken sensor probe, a disconnected or corroded wiring harness connector at either the sensor end or the control board end, and damaged wiring along the sensor circuit run. In rarer cases, the control board itself may have a failed input circuit for the sensor. Because the self-clean cycle exposes the sensor to extreme temperatures, F31 faults are frequently triggered immediately after or during a self-clean cycle when sensor degradation accelerates.

Source: manufacturer service documentation.

Common causes of F31

  1. 01

    Failed oven temperature sensor

    Part replacement

    The sensor probe itself has developed an internal open circuit, often after prolonged use or exposure to the extreme heat of a self-clean cycle. A properly functioning sensor will show a measurable resistance across its terminals; an open sensor will read infinite resistance (OL) on a multimeter.

  2. 02

    Disconnected or loose wiring connector

    Wiring / connection

    The connector at the back of the sensor probe or at the control board may have worked loose due to heat cycling or vibration. Inspect both ends of the sensor wiring harness for connectors that are not fully seated or have pulled apart.

  3. 03

    Damaged sensor wiring harness

    Part replacement

    The wires running from the sensor through the oven cavity can become brittle, pinched, or burned over time, causing an open circuit in the line. Visually trace the full length of the harness for any visible breaks, melted insulation, or wire contact with hot oven surfaces.

  4. 04

    Corroded or burned connector terminals

    Wiring / connection

    High heat and moisture can corrode the pin terminals inside the sensor harness connectors, increasing resistance to the point of an effective open circuit. Check the connector pins for discoloration, pitting, or buildup that would interrupt the electrical path.

  5. 05

    Faulty control board sensor input

    Part replacement

    If the sensor and all wiring check out correctly, the sensor input circuit on the control board may have failed, causing the board to incorrectly report an open circuit. This is the least common cause and is typically diagnosed only after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about F31

What does F31 mean on a Bosch range?
F31 means the control board has detected an open circuit in the oven temperature sensor circuit while a cook or clean cycle was running. The sensor is responsible for continuously reporting oven temperature, and when the signal is lost for more than 20 seconds, the oven locks out heating and displays F31. This is a safety response to prevent uncontrolled oven temperatures.
Can I reset F31 on my Bosch range to clear the error?
You can clear the code by powering the range off at the circuit breaker for about 30 seconds and then restoring power. However, if the underlying open circuit condition still exists in the sensor or wiring, the fault will return within 20 seconds of starting a cook or clean cycle. A reset alone is not a repair and should only be used as part of diagnosing whether the fault is intermittent.
Is it safe to use my Bosch range when F31 is displayed?
Surface burners on a gas or dual-fuel range may still operate, but the oven should not be used while F31 is active. Because the control board has no reliable temperature data, it cannot regulate oven heat properly, creating a risk of overheating. Avoid using the oven until the sensor or wiring fault is resolved.
How do I fix F31 on a Bosch range?
Start by inspecting the sensor wiring harness for any disconnected connectors, visible wire damage, or burned insulation, as these are the easiest and lowest-cost issues to address. If the wiring is intact, test the sensor itself with a multimeter for continuity and resistance. An open reading on the sensor means it needs to be replaced. If both the sensor and wiring are good, the control board may need evaluation by a qualified technician.
How much does it cost to repair a Bosch range F31 error?
If only the oven temperature sensor needs replacement, parts typically range from around 20 to 80 dollars depending on the specific model, with additional labor costs if a technician performs the repair. Wiring harness repairs or connector replacements are generally on the lower end of the cost range. A control board replacement, if required, is significantly more expensive and can range from 150 to 400 dollars or more for parts alone.

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