BMW Z3 Speedometer Error: Multiple Systems Failing

Hey there! I had a similar issue with my 2004 BMW Z4 last summer. The symptoms were almost identical, warning lights, error messages, and system failures. Turned out the radar sensor was just really dirty! Took it to my regular workshop, and the mechanic cleaned the sensor thoroughly and recalibrated it. Total cost was around 45 Euro, which was a relief because I was worried it would be something major. Since then, everything's been working perfectly on my Bimmer. Before I can share more specific advice, could you share: Are there any specific warning lights that come on? Does it happen more in certain weather conditions? Have you noticed if the sensor area is visibly dirty? Also, if you own a different Z3 model than mine, the setup might be slightly different, so those details would help too.

Just had my latest service done last week, and with 125599 KM on the clock, I can confirm this sounds exactly like what I experienced a few months back! In my case, it wasn't just a dirty sensor, turned out the wiring harness near the sensor was damaged and causing all those crazy warning lights and errors. The insulation had worn out over time and was causing shorts. Definitely get it checked out properly, these old Z3s can be tricky with electrical gremlins. The radar sensor itself was fine after testing, but the wiring was the real culprit. Cost me a bit more than just a cleaning, but still way better than replacing the entire sensor unit. My mechanic had to rewire that section and weatherproof it properly. Let me know if you need more details about what they did to fix it. Always happy to help another Z3 owner!

Hey again! You know, after reading about your wiring harness issue, I feel a bit embarrassed about my initial response suggesting just a dirty sensor! I had similar symptoms with my Z4, and while cleaning the sensor worked for me initially, I actually ended up having the exact same wiring problem a few months later. Those warning lights came back with a vengeance! My mechanic found corroded wiring near the sensor connection, pretty much identical to what you described. The insulation was totally shot, and every time it rained, things would go haywire. Looking back, I should've done a more thorough check instead of assuming it was just dirt. Had to shell out for proper rewiring and weatherproofing, but it was worth every penny. These BMWs are fantastic cars, but they sure can throw some curveballs with their electronics! The good news is, once you fix the wiring properly, the problem stays fixed. Haven't had a single warning light since the repair. Thanks for sharing your experience, it really helped confirm what eventually happened with my car too. These older BMWs seem to have this as a common weak point.

Thanks so much for the additional info about your Z4! It's actually really reassuring to hear that others have gone through the same thing. You're absolutely right about not needing to feel embarrassed about suggesting the dirty sensor, honestly, that's always a good first check before diving into bigger repairs. What's really interesting is how similar our experiences ended up being, despite having different models. I guess BMW used similar wiring setups across their range during that period. My mechanic actually mentioned that rain-related issues are a classic sign of wiring problems in these cars. I'll definitely take it in next week to get it checked out. After hearing both your experiences, I'm pretty confident it's going to be a wiring issue rather than just a dirty sensor. Better to fix it properly now than have it keep coming back. Really appreciate everyone taking the time to share their experiences. There's nothing quite like hearing from people who've actually dealt with the same problems firsthand. I'll update once I get it sorted!