B101B13 - Crash sensor, passenger front airbag, open circuit airbag control unit fault

What does error code B101B13 mean in the airbag control unit?

Error code B101B13 reports an open circuit in the crash sensor circuit for the passenger-side front airbag. The airbag control unit can no longer reach the sensor, stores the fault and switches on the airbag warning light.

The control unit monitors the sensor circuit continuously. If the connection stays open, it detects this and can no longer control the passenger's front airbag reliably in an emergency. The sensor supplies the control unit with the data it uses to decide, in an impact, whether to deploy the passenger's front airbag. If the connection is interrupted, this information is missing. Behind the base code is the fault type, here the open circuit.

How do you recognise error code B101B13?

The airbag warning light in the instrument cluster stays on permanently. The code can be read from the fault memory with a diagnostic tool and returns after being cleared.

• Permanently lit airbag warning light.
• Entry in the fault memory of the airbag control unit.
• The fault cannot be cleared permanently.
• Driving behaviour and the engine stay unchanged, only the airbag protection is limited.

What causes error code B101B13?

With an open circuit, the wiring, the connector, the crash sensor and the airbag control unit are all possible causes. After an accident with damage, the sensor's wiring may also be affected.

• A detached or corroded connector.
• A broken wire to the crash sensor.
• A faulty sensor that no longer lets current through.
• A fault in the control unit, for example at aged solder joints or due to moisture.

In a control unit that has been through an accident, crash data may also be stored.

In which vehicles does error code B101B13 occur?

Error code B101B13 is known in the Audi A4 B9. The information is not complete, and in other vehicles or makes the code may mean something different.

Whether it refers to the same thing in your vehicle is shown by the fault memory that has been read out. The code belongs to the airbag control unit and not to the engine or the chassis electronics.

How is error code B101B13 resolved?

The fault memory is read out first with a diagnostic tool. A specialist workshop checks the connector, wiring and crash sensor. If the fault is in the airbag control unit, it can go to Airbag24 for repair.

If the check shows no fault at the connector, the wiring or the sensor, the cause lies in the control unit. To send it in, disconnect the battery, remove the control unit, create a repair order online and send the unit in. Checking, repairing and testing usually take 3–4 working days.

The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

Work on the airbag system belongs in expert hands. This applies to removing the control unit just as much as to any check of connectors, wiring and sensors.