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Issue with the front left airbag mechanism Attend a session

Posted: Thu Feb 19, 2026 9:26 am
by killiomop
Issue with front left airbag - please consult workshop

Neither the engine light nor the airbag light are illuminated on my dashboard, as shown above. In 2014, the owner purchased a W246 B Class B180.


A diagnostic tool that I hooked up to the on-board diagnostics system has given me the following information: passenger sensor mat fault (B275296).

But when I get in the passenger seat, the device knows I'm a passenger, and it even takes the seatbelt into account. Therefore, I do not know whether the mat is the mistake or not.

The ignition circuit with component K88 (Pyrotechnical separator) has a resistance value of zero ohms, as I have checked the resistances.

Since the seat mat seems to be functional, I am investigating any other potential problems; thus, is this ignition circuit resistant?

Re: Issue with the front left airbag mechanism Attend a session

Posted: Thu Feb 19, 2026 9:30 am
by LiamTheGreat
If your scanner indicates that the front occupancy sensor pad requires replacing, then it's true; I had the same issue with mine. It functioned properly with a passenger, but when there was only me in the car, the dashboard alerted me to an impending danger. The airbag light has to be on for it to be considered a failed MOT, but I had to prove it to my tester before he could fail me for it, so I rectified it.You have two options: either replace it (which isn't exactly a picnic), or install an emulator. The latter simply plugs into the same socket as the current sensor and tricks the car into thinking someone is sitting there at all times. The only drawback is that in the event of an accident, both the driver's and passenger's airbags will deploy, which is a minor inconvenience compared to the severity of the crash. Putting a rear-facing child seat there obviously disqualifies this method.

Re: Issue with the front left airbag mechanism Attend a session

Posted: Thu Feb 19, 2026 9:30 am
by killiomop
Thanks for getting back to me. When a passenger is seated in the seat, the warning message is also displayed on the dashboard. Once I plug in the icarsoft device, I can now see that the mat and belt are detected when a passenger gets in the seat and fastens the buckle.
So far, I haven't been able to determine whether the issue lies with the mat or any other component. Curiously, I could see that water had seeped in through the door and saturated the back driver's side footwell shortly after this occurred. I can't tell if this is relevant because I didn't notice any cords in the footwell.

Re: Issue with the front left airbag mechanism Attend a session

Posted: Thu Feb 19, 2026 9:31 am
by GoodWillHunt
Mmm, that's a little different. It was ideal when my wife was in the seat. Without fail, the seat belt alert functioned as intended. A replacement mat solved the problem.