Problems with black smoke and power loss in 2004 BMW 3 Series - possible causes and solutions

Hey, I can well understand your worries. I had roughly the same story with my Audi A4 diesel. The people at my garage then said that the DPF had not been regenerated properly. Apparently, this can happen if you mainly drive short distances and the filter does not reach the desired operating temperatures as a result. In my case, the solution ultimately looked like this: they carried out a so-called "forced regeneration". This is basically an artificially induced cleaning process in which the filter is brought to a higher temperature so that the remaining particles burn off and the filter is cleaned. It worked perfectly for me and I haven't had any more problems with this issue since.

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Hey, I had exactly the same problem with my 2006 BMW 3 Series, which unfortunately resulted in a defective diesel particulate filter due to high mileage. I then took the car to my regular garage, which specializes in this. They then replaced the part and it cost me 1250 euros. Your engine sounds a bit different, but it may be the same. What model do you have and how many kilometers does it have on it? That might help to narrow down the problem. Hope this helps you!

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Hey, thanks for your quick reply! It already has a good 224851 km on the clock. If it really is the diesel particulate filter, then that's annoying of course, but what the heck. I was hoping it might be something else.

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Hey, that's really interesting about the "forced regeneration", I haven't heard that before. I'll definitely talk to my workshop technician about it. Thanks again for your help!

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