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TommyB

Problems with BMW 6 Series Diesel 2003: Black smoke, starting difficulties and faulty DPF regeneration

Shaking while idling

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Pre-glow light won't turn off

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Longer cold start time

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Car won't start

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Black smoke from exhaust on acceleration

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DPF regeneration failure

Hey guys, my BMW 6 series diesel, built in 2003, is experiencing some strange problems. Black smoke is coming out of the exhaust when accelerating, it takes much longer to start when cold and the DPF regeneration is failing. In addition, the car won't start, the preheating light won't go out and it vibrates when idling. Could this be due to a defective glow control unit? Have you experienced similar problems and how did you solve them? All tips and experiences are welcome! Thanks in advance!

(Translated from German)

39 comment(s)


NicoWag91

Hello, I had a similar problem with my 2001 BMW 5 Series diesel. I'm definitely not an automotive expert, I just have some experience with cars. We had the control unit replaced in the workshop because it was defective. According to the mechanic, that was the most common cause of the fault. It cost about 1000 euros and then the problems were gone. Before I give you specific advice, it would be helpful if you could tell us a bit more about your car, for example how many kilometers it already has on the clock and when it was last serviced. I hope this helps you!

(Translated from German)

TommyB (Author)

Hello, thanks for your reply! My old car already has 278164 km on the clock and the last service was only recently. I will follow your advice and have the control unit checked. Best regards!

(Translated from German)

Best Answer

NicoWag91

Hi, thanks for the info! With this high mileage and the age of the car, there could be several things causing the problems. A faulty glow control unit could definitely be behind the symptoms, especially with the starting problems you mentioned and the pre-glow lamp not going out. In my 5 Series, for example, the DPF was also clogged - this could also be the case for you, especially if the regeneration is no longer working. Professional cleaning or even replacement would be advisable here. That also helped with my car. I would therefore recommend that you have the car checked by a specialist. As some defects can also promote each other, you should, if possible, address both points (glow control unit and DPF) promptly. This may save you a visit to the garage or two. But as I said, I'm no expert - this is just my personal experience. Good luck and keep us up to date!

(Translated from German)

TommyB (Author)

Hi, thanks for your detailed tips! I will have the car looked over by a specialist first and check both the glow control unit and the DPF. That's very helpful advice from you, thank you for sharing your experiences. I will definitely keep you posted. Have a nice weekend!

(Translated from German)

Robin

I also had black smoke coming out of my 2004 320d e46. I also have a defect glow control but I just ignored that. For me the issue was a ripped charge air pipe. I replaced that and my airflow sensors and it’s running fine again. So the glow control unit has no impact on the black smoke.

CarlyAdminBenny

@Robin

I also had black smoke coming out of my 2004 320d e46. I also have a defect glow control but I just ignored that. For me the issue was a ripped charge air pipe. I replaced that and my airflow sensors and it’s running fine again. So the glow control unit has no impact on the black smoke.

Thank you very much for your answer, and thank you for sharing your experience with us ;)

(Translated from German)

ste.buck1971

I changed the glow plug relay and the egr valve and my car runs sweet now. It hadn’t regenerated for so long but has done one now.

Rhyss

Hi i have a e46 320d 2005. im experiencing misfiring around 2000/2500 and sometimes i lose all power altogether, carly saying glowplugs wondering if it is the glow plugs or the control unit before i spend money and waste my time. Thanks

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