Fault code B1201 – a step-by-step guide to diagnosing and fixing it

Error code B1201 is displayed and the check engine light is on - what does this mean?

The DTC B1201 is recognized by the OBD/EOBD system and indicates a problem in the airbag system, specifically with the driver airbag circuit. This fault code relates to the vehicle's safety systems and can have different specific meanings for different manufacturers, but generally refers to faults in the airbag electronics.

What causes can this fault code have?

• Defective driver airbag
• Damaged wiring in the airbag circuit
• Loose or corroded plug connections
• Defective airbag control unit
• Interrupted spiral cable connection in the steering wheel
• Short circuit in the airbag wiring
• Defective crash sensor
• Weak or defective vehicle battery

What symptoms occur in parallel with fault code B1201?

• Airbag warning light: The airbag indicator light lights up continuously or flashes in the dashboard
• Function failure: The driver airbag may be deactivated and does not work in an emergency
• Steering wheel problems: Horns or other steering wheel functions may be impaired
• Starting problems: In rare cases, starting problems may occur if the control unit is affected
• Additional warning lights: Additional safety system warning lights may be activated

How to fix the problem of trouble code B1201?

• Fixing trouble code B1201 requires systematic diagnosis and precise repair measures.
• Read out the airbag system with a professional diagnostic device and analyze all stored fault codes, then check the coiled cable in the steering wheel for continuity and replace it completely if it is defective
• Disconnect all plug connections in the airbag circuit, clean, check for corrosion and reconnect firmly, paying particular attention to the connections under the seats
• Locate the airbag control unit, measure the voltage supply and replace the entire control unit with a new or reconditioned one if there are any deviations
• Fully charge or replace the vehicle battery, check all electrical connections to the battery and delete the fault memory after replacing the battery
• Remove the driver airbag module in the steering wheel, measure the resistance values and replace the entire airbag module professionally if defective
• Locate crash sensors in the vehicle, check for mechanical damage and replace defective sensors with original parts