BMW M3 Hood Sensor Warning Puzzles High-Mileage Owner

Had the same issue on my 2016 BMW M4 last year. The acceleration sensor was defective, which controls both the active hood deployment and feeds into the airbag system, that's why you're seeing both warnings. When I brought it in, the diagnostic showed the sensor had corroded internally. It's a critical safety component, so I wouldn't recommend driving too long with this fault. The repair involved replacing the acceleration sensor unit and recalibrating the system. The garage needed to keep the car for two days because they had to run several tests after the replacement to ensure proper function of both the hood and airbag systems. It's actually a fairly common issue on these models once they get higher mileage. Just make sure whoever works on it has experience with BMW safety systems, it's not something you want a general mechanic messing with.

Hey, thanks for sharing your experience! It's really helpful to know about the acceleration sensor being the culprit. That definitely sounds like what's happening with mine too. Would you mind sharing how much you ended up paying for the whole repair? Also curious if you've had any related issues pop up since getting it fixed? Really want to make sure I budget properly for this and know what to expect down the road. The M3's been great otherwise, but these sensor issues can be tricky!

Hey again! Glad I could help with the info about the sensor. Just wanted to follow up, got the repair done last week and yep, it was exactly what I thought: faulty acceleration sensor. Cost me 315 € to get it sorted, which included the part replacement and all the testing they had to do. The Active hood fault message is completely gone now, and everything's working perfectly. Since you asked, I've had zero issues since getting mine fixed last year. The sensor replacement seems to be a proper long-term fix, not just a temporary band-aid. My M4's running like a charm now. Looking back, it was definitely worth getting it sorted quickly rather than letting it drag on. Quick tip though, make sure you keep all the paperwork from the repair. These sensors are part of the safety system, so it's good to have documentation that it was properly fixed if you ever decide to sell the car. Just my two cents from going through the same thing!

Thanks so much for all the detailed info! Just got back from seeing a certified BMW mechanic today. You were spot on, it was the acceleration sensor. They quoted me slightly higher at 360 €, but I went ahead with the repair since the car's safety was at stake. The whole process was actually smoother than I expected. Dropped it off in the morning, and they had it ready by late afternoon. The mechanic showed me the old corroded sensor, pretty wild how such a small part can trigger multiple warning systems! They ran all the safety checks, and now both the active hood and airbag warnings are completely gone. Really glad I asked here first. Made me feel way more confident walking into the shop knowing exactly what to expect. And good call on keeping the paperwork, got everything documented and filed away. Thanks again for helping me avoid another frustrating mechanic experience!