BMW Z3: Headlight and Speedometer Issues Need Help

Hey there! I have some experience working on BMWs, having owned a 2004 BMW Z4 before switching to my current 3 Series. I actually faced a very similar issue. The symptoms were exactly like yours, warning lights, wonky headlight alignment, the whole deal. After taking it to my regular workshop, they diagnosed a faulty headlight servomotor. The repair set me back about 1,040 Euro, but it fixed all the problems at once. Before I share more specific details about my repair experience, could you share: Have you noticed any unusual noises when the headlights adjust? Did these issues start gradually or all at once? Have you had any recent work done on the electrical system? This info would help me understand if you're dealing with the same root cause I had.

Thanks for sharing your experience! My Z3 has 129462 KM on the clock and was just serviced last month. Regarding your questions, the issues started pretty suddenly, no weird noises from the headlights, and no recent electrical work. Was your repair involving just the servomotor replacement, or did they need to swap out other components too? Just trying to get an idea of what I might be looking at cost-wise. Really hoping it's not as expensive as your repair.

Hey again! Thanks for those details about your Z3. Yeah, I get why you're hoping for a lower repair cost, I remember that feeling well! In my case, while the servomotor was the main culprit, they actually had to replace the entire headlight leveling control unit along with it. The workshop found that the original control unit had some corrosion damage that was causing it to send incorrect signals. That's why my repair ended up being so pricey. But here's some good news, since your car has lower mileage than mine did when this happened (mine was at 175,000 km), and the issues started suddenly without any weird noises, you might just be dealing with a simpler problem. Could be just the servomotor or even just a wiring issue. Quick tip: before you take it in, check your fuse box if you haven't already. I really wish I'd done that first because sometimes it can be as simple as a blown fuse. Would've saved me some diagnostic fees! Let me know what you find out when you get it checked. Really curious if it turns out to be the same issue as mine or something different.

Thanks for the detailed info and the tip about checking the fuse box! I'll definitely look into that first, can't believe I didn't think of checking something so basic. Really hoping you're right about it potentially being simpler in my case. The idea of just having a wiring issue or single component replacement sounds much better than your full control unit situation. I've scheduled an appointment with my mechanic for next week, but I'll check those fuses tonight when I get home. Will probably save myself some embarrassment if it turns out to be just that! I'll keep you posted on what they find, fingers crossed it's not going to empty my wallet like your repair did. Really appreciate you taking the time to share your experience!

Hello, My BMW E46 320i with the M54B22 engine is throwing a bunch of error codes: lean air-fuel mixture, lambda deviation, misfire on cylinders 1-6. However, if I clean it and drive, the car runs perfectly. But if I let it sit idle for a while, the engine eventually revs up and loses its idle. I've already replaced the DISA valve, and the camshaft position sensors (intake and exhaust).

(Translated from French)

Start by checking for any vacuum leaks, as these can cause a lean air-fuel mixture and misfires. Inspect the intake boots, vacuum hoses, and the crankcase ventilation system for any cracks or disconnections. A smoke test can be particularly effective in identifying hard-to-find leaks. Let me know if you find anything or if you have further questions!