BMW Diesel NOx Issues: Engine Light and Power Loss Help

Hey! I've got some experience with cars, and I dealt with something very similar on my 2011 BMW 3 Series diesel. Like you, I had the engine light, power issues, and failing emissions. After checking several workshops, I found one that specialized in BMW diesels. Turned out there was a significant leak in the exhaust system right before the NOx catalyst. The whole repair, including parts and labor, cost me 265 Euro. After fixing it, all the symptoms disappeared and the car runs perfectly now. What's your exact model (320d, 218d, etc.)? And how many miles/kilometers are on it? This info would help me tell you more specifically if you're dealing with the same issue I had. Word of advice: Don't wait too long to get it checked out. These issues tend to get worse and more expensive if left unattended.

Thanks for sharing your experience! I've got a 218d with 101026 KM on the clock, and my last service was about 3 months ago. Your situation sounds exactly like what I'm dealing with. Good to hear you managed to fix it without breaking the bank. I'll definitely look for a BMW specialist to check it out soon. Were there any warning signs before your exhaust started leaking? Just wondering if I should've caught this earlier.

Hey again! Thanks for the follow-up. Yeah, with your 218d having similar symptoms, it's probably the same issue I dealt with. Looking back, there were actually a few warning signs before things got really bad, and I wish I'd paid more attention to them. First, I noticed a slight rattling noise when accelerating, especially when the engine was cold. Then there was this weird sulfur smell, but it was pretty faint at first. The power loss came gradually too, it wasn't sudden, but the car felt less responsive over time. With your mileage being pretty close to what mine was when I had the problem (I was at around 98000 KM), it makes even more sense. These NOx systems tend to start showing their age around this point. Just be careful if you're planning to drive it much before getting it checked. When mine started acting up, I waited about two weeks before taking it in, and the leak got noticeably worse during that time. The mechanic told me I was lucky I didn't wait any longer, as it could've damaged other components. By the way, after my repair, I noticed a huge difference in fuel consumption too, dropped about 0.8L/100km. Hadn't even realized how much the leak was affecting that! Let me know how it goes when you get it checked out. Really curious if it's the same issue!

Thanks so much for all those details! That's really helpful to know about the warning signs. Now that you mention it, I did notice a faint rattling noise a few weeks ago but didn't think much of it at the time. And yes, my fuel consumption has definitely gone up lately, makes total sense now! I've actually just booked it in with a BMW specialist for tomorrow morning. Don't want to risk making things worse by waiting. Really appreciate you taking the time to share your experience, it's made me feel a lot more confident about what I'm dealing with. The fact that your repair wasn't too expensive is also reassuring. I'll let you know how it turns out after I get it checked. Thanks again for all your help!