What causes the disappearance of BMW's seat belt automatic tightening function?
2 Answers
BMW's seat belt automatic tightening function may disappear due to being turned off in the central control settings or hardware failure. Turned off in central control settings: BMW's seat belt automatic tightening electronic control device is usually used in combination with auxiliary airbags. If the seat belt automatic tightening function disappears, first enter the settings option in the central control screen to check if it has been turned off. Hardware failure: The seat belt pre-tensioning device is built into the seat belt and consists of a seat belt retractor and a seat belt tension limiter. Dirty or stuck seat belts, damaged electric motors, etc. can cause this situation. It is recommended to go to a repair facility for handling.
I recently helped a friend deal with the failure of the BMW seatbelt pretensioner function. This feature relies on the pretensioner system, and sudden disappearance may be due to a sensor malfunction, especially after driving on bumpy roads. It could also be caused by loose or oxidized wiring connections leading to poor contact, so the wiring harness under the steering wheel needs to be checked. Control module failure is another common cause, such as water damage or aging. I recommend listening for any sound from the seatbelt when starting the vehicle—if there’s none, use an OBD diagnostic tool to read the fault codes first. Never ignore this issue, as emergency braking protection will be compromised while driving. Go to a 4S shop for professional inspection immediately to avoid minor issues turning into major repairs. Safety first—prevention is always better than regret afterward.
