BMW 5-Series Exhaust Flap Failure Causing Loud Noise

I had the exact same issue with my 2020 BMW M340i last winter. The exhaust flap actuator failed completely, causing that loud cold start you're describing. Initially thought it was just the cold weather, but the error code confirmed it was the actuator. My experience at the garage revealed the vacuum lines were intact, but the actuator itself was shot. They had to replace the entire actuator unit and reprogram the exhaust control module. It wasn't a major mechanical issue affecting engine performance, but leaving it unfixed would've kept the exhaust permanently in the loud setting. The repair took about 2 hours. While not a complex fix, it needs proper diagnostic equipment and coding to get everything working correctly. Just make sure you go to someone who knows BMW systems well, it's not just about swapping parts. Worth getting it sorted soon before winter hits. The constant loud exhaust gets old pretty quick, especially on cold mornings.

Thanks for sharing your experience! Really helpful to hear from someone who went through the same thing. I'm planning to get it fixed soon, the noise is definitely getting annoying. Would you mind sharing how much you ended up paying for the repair? Also curious if you've had any other issues pop up with the exhaust system since getting it fixed?

Hey again! Just wanted to follow up on your questions. I got my M340i fixed and it cost me 190 € for the whole job, that covered the actuator replacement and reprogramming. Looking back, it was totally worth it! Since getting it sorted, the exhaust system has been working perfectly, no more unexpected concert-level noise in the morning! The flaps are now operating exactly as they should, switching between comfort and sport modes smoothly. Such a relief not having to apologize to the neighbors anymore for those loud cold starts! Honestly, it was one of those repairs that made me realize sometimes it's better to just bite the bullet and get things fixed properly. Haven't had a single exhaust-related issue since then, and it's been really nice having full control over the exhaust sound again. If you're still on the fence about getting it fixed, I'd say go for it. The peace of mind is worth the investment, and it's not as expensive as some other BMW repairs can be. Just make sure you find a good mechanic who knows their way around these systems.

Just wanted to update everyone about my BMW exhaust situation. Finally got up the courage to visit a different mechanic yesterday, and I'm glad I did! The whole experience was actually much better than expected. Turned out my issue was pretty similar, faulty actuator and some worn vacuum lines. The repair bill came to around 210 € total, bit more than what you paid, but still reasonable. The mechanic was super professional and even showed me the old parts. The best part? My car's back to normal now! No more embarrassing loud starts or weird noises. The exhaust flaps are working perfectly, switching modes just like they should. Really wish I hadn't waited so long to get it fixed. Thanks again for pushing me to get it sorted. Having a quiet morning start today was absolutely worth every penny spent. Now I can finally stop worrying about waking up the entire street!