BMW 7 Series DPF Woes: Smoke and Warning Light Issues

Had the exact same issue on my 2004 BMW 5 Series diesel last month. The symptoms matched yours perfectly, warning lights, rough running, and that nasty smoke under load. Took it to my regular garage and they confirmed it was the exhaust back pressure sensor. The mechanic showed me how the sensor was sending incorrect readings to the ECU, which messed up the DPF regeneration cycle. They had to replace the sensor and reset the ECU. It wasn't a major repair, but leaving it unfixed would've caused bigger problems with the DPF system over time. The whole job took about 2 hours. Since the fix, the car's been running smoothly with no warning lights or smoke. Just make sure whoever works on it uses genuine BMW parts for the sensor. Some aftermarket ones can cause more problems than they solve.

Hey, thanks for sharing your experience! It's really helpful to know that replacing the sensor fixed the issue for you. I had similar work done on my BMW and your symptoms sound spot on with what I experienced. Just curious, do you remember roughly how much you ended up paying for the repair? Also, has everything been running smoothly since then, or have you noticed any other quirks popping up? These BMWs can be tricky sometimes, but they're worth it when they're running right!

Hey there! Yeah, no problem at all, happy to help! The total bill came to 245 € for fixing that pesky exhaust back pressure sensor. Honestly, it was money well spent because the car's been running like a dream since the repair. No more warning lights, smoke, or any of that drama we discussed earlier. My 5 Series is purring along perfectly now, it's amazing what replacing one faulty sensor can do! The mechanic did a proper job with the genuine BMW part, and I haven't had a single issue pop up since. The DPF's working exactly as it should, and the engine's running super smooth. I totally get what you mean about BMWs being tricky sometimes, but when they're properly sorted, they're absolutely brilliant machines. Just keep an eye on your sensor readings and maintenance schedule, and you should be good to go. Worth every penny if you ask me!

Thanks for the info about the cost and follow-up! Just wanted to update you on my situation. I bit the bullet and took my car to a mechanic last week. Turned out you were spot on, it was definitely the exhaust back pressure sensor causing all the trouble. The repair cost me a bit more, around 300 €, but they also did a full diagnostic check while they were at it. I've put about 500 km on it since the fix, and what a difference! No more warning lights, the smoke's completely gone, and it's running better than ever. The mechanic I found was actually great, really took the time to explain everything and showed me the old sensor. It was completely shot, no wonder the car was acting up! Really glad I got it sorted before it caused any serious damage to the DPF. These BMWs might be high maintenance sometimes, but when they're running right, they're absolutely worth the hassle. Thanks again for helping me make the decision to get it checked out!