Fault code B1811 – a step-by-step guide to diagnosing and fixing it

Error code B1811 is displayed and the check engine light is on - what does this mean?

The DTC B1811 is a body code that is recognized by the OBD/EOBD system and indicates a problem with the airbag system or the vehicle body electronics. This fault code mainly relates to the airbag control unit and can have different specific meanings for different manufacturers.

What causes can this fault code have?

• Defective airbag sensor
• Damaged cable in the airbag system
• Loose plug connections on the airbag control unit
• Defective airbag coil cable (slip ring)
• Faulty airbag control unit
• Corrosion on the airbag contacts
• Low battery voltage
• Defective belt tensioner sensor

What symptoms occur in parallel with fault code B1811?

• Airbag warning light: The airbag indicator light lights up continuously or flashes
• Function failure: Airbag system may be deactivated
• Seat belt tensioner problems: Automatic seat belt tensioner does not work
• Warning messages: Error messages in the vehicle display
• Safety risk: Reduced occupant protection functionality

How to fix the problem of error code B1811?

• Repairing error code B1811 requires systematic diagnosis and professional implementation.
• Carry out a complete OBD diagnosis and read out all stored fault codes, then reset the airbag system and carry out a test drive
• Check the airbag coil cable on the steering wheel and replace completely if damaged or worn
• Check all plug connections of the airbag system for tight fit and corrosion, clean and reconnect
• Replace the airbag control unit if the diagnostic device indicates an internal defect in the control unit
• Measure the battery voltage and charge or replace the vehicle battery if the value is below 12V
• Locate defective airbag sensors and replace with new original parts