BMW Z3 Airbag Light & Convertible Top Problems, Need Help!

Hey there! I had a pretty similar issue with my 2003 BMW Z4 last summer. I've got some experience working on cars, but electrical stuff isn't really my thing. The airbag warning light was driving me nuts, and like yours, my convertible top was acting weird. Took it to my regular workshop and it turned out to be a faulty control unit. The repair set me back about 1000 Euro, but it fixed both issues completely. They had to replace the control unit and recalibrate the system. Can you share what error code you're getting? Also, does your top make any unusual noises when trying to close? These details would help determine if you're dealing with the exact same problem I had with my Z4. Plus, knowing your car's mileage might be helpful too. My sister has a BMW M3 from the same era, and these control units can be a bit tricky in these models. Let me know the details, and I might be able to help more!

Thanks for sharing your experience! My Z3 has done 32711 KM and had its last service about three weeks ago. The error code I'm getting is B7245, and yeah, the top makes this weird grinding noise when closing, especially during the last few inches. It's super frustrating because it used to work perfectly fine until recently. I was hoping to avoid a costly repair, but hearing about your similar experience with the control unit makes me think I might need to bite the bullet and get it checked out professionally. Did your workshop mention anything about common failure points for these control units? I'm trying to figure out if this is a typical issue for our generation of BMWs.

Hey again! Thanks for those extra details about your Z3. Yeah, that B7245 code is exactly what I got with my Z4, it's like déjà vu! And that grinding noise you mentioned? Spot on, mine did the same thing. When I took mine in, my mechanic actually explained that these control units are pretty notorious for failing in our generation of BMWs, especially after they hit around 30,000-35,000 KM. It's kind of a known weak point. The funny thing is, my car had just been serviced too when these issues started popping up. Since you mentioned trying to avoid costly repairs (trust me, I tried that too!), I should warn you that I actually made things worse by waiting. The grinding noise got really bad, and I was worried it might damage other components. The repair cost might seem steep, but it's definitely cheaper than dealing with multiple issues if something else gets damaged. Quick tip though, my mechanic mentioned that sometimes these units can be refurbished instead of replaced completely. Might be worth asking about that option when you take it in. Saved a couple hundred bucks on my repair that way. Let me know what you end up doing. I'm really curious if your fix turns out similar to mine!

Thanks everyone for the helpful responses! Yeah, after hearing about these similar experiences, especially with that identical error code and grinding noise, I think I need to get this sorted sooner rather than later. It's a bit reassuring to know I'm not the only one who's faced this issue, even though the repair cost isn't exactly thrilling news. I'll definitely look into that refurbishment option, that's a really good tip! I've already called a few BMW specialists and got an appointment for next week. Better to fix it now than risk more damage to the convertible top mechanism. Will keep you posted on what they find and if it ends up being the same control unit problem. Really appreciate all the advice and shared experiences, it's helped me feel more confident about tackling this repair head-on!