BMW 7 Diesel Glow Plug Issues: Causes and Solutions

Hi there! I had similar issues with my '12 BMW 5 Series diesel. Initially thought it was just the glow plugs, but after a proper diagnosis, it turned out the glow plug control module had failed, plus two glow plugs were shot. The black smoke and cold start problems are classic signs. Last month, the garage found corroded connections between the control module and the plugs, which was causing voltage drop issues. Got the module replaced and all glow plugs changed as a set, seems wasteful but it's best practice. They also cleaned the intake while they were at it. It was a serious repair that needed immediate attention since bad glow plugs can damage your engine and the black smoke means you're not burning fuel efficiently. Mine took about 6 hours of labor because they had to remove quite a bit to access everything properly. The car runs like new now, starts instantly even in cold weather, no more smoke, and passed emissions with flying colors. Would definitely recommend getting it sorted soon before it causes more problems. Hope this helps with your decision.

Thanks for sharing your experience, that's exactly what I was dealing with! Great to hear you got it sorted. Would you mind sharing what the total repair cost was? Also, just curious if you've had any similar issues pop up since the fix? I'm trying to budget for this and want to make sure I'm prepared if there's anything else I should watch out for.

Hey again! Great to give you an update, after taking your advice, I got it fixed last week. Turns out I was lucky, it was just a faulty connection at the glow control unit, not nearly as extensive as my initial repair. Only cost me 95 € to fix the cable and connection issue. Way cheaper than what I paid for my previous repair! Since the fix, my car's running perfectly, starts right up in cold weather with no hesitation, and there's zero black smoke now. Haven't had a single glow plug warning light come on since. Honestly wish I'd done it sooner! The mechanic did mention it's worth keeping an eye on the glow plugs themselves over the next year or so, just as preventive maintenance, but there's no immediate concern. They typically last quite a while if the control unit is working properly. Really glad I could help point you in the right direction. These diesel issues can be tricky, but once you get them sorted, they usually stay fixed for good! Let me know if you need any other advice!

Hi again! Thanks for sharing back! You were totally right about getting it checked promptly. I finally took my car to the mechanic yesterday. The diagnosis showed it was definitely the glow control unit, but they also found two bad glow plugs. The whole job, including parts and labor, came to about 450 bucks. I was pretty relieved, thought it would cost way more after hearing about some other repairs. The mechanic I found was really straightforward and even showed me the old parts. They did the whole job in about four hours, and now my car's running like a dream! No more black smoke, starts perfectly in cold weather, and the warning light's finally gone. Best part is, they said with this fix, I shouldn't have any similar issues for quite a while. They recommended I just keep up with regular maintenance and maybe check the remaining glow plugs in about a year. Really appreciate your help, definitely made me feel more confident about getting it sorted. Thanks for pointing me in the right direction!

Faults 004203 BMW 320d e90 M47

(Translated from French)

The fault code 004203 on a BMW 320d E90 with the M47 engine typically relates to the glow plug control module or the glow plugs themselves. Start by checking the connections to the glow plug control module for any signs of corrosion or damage. If the connections are fine, you may need to test the glow plugs individually to see if any are faulty. If you're unsure or uncomfortable with these checks, it's best to have a professional mechanic inspect it, as faulty glow plugs can affect engine performance and emissions. Let me know how it goes or if you have any other questions!