BMW 7 Hybrid ABS Failure: Speed Sensor or Worse?

Hi there! I have some experience working on cars, and I actually faced a similar issue with my 2014 BMW 5 Series Hybrid (I also own a 3 Series). The symptoms you're describing sound exactly like what I encountered, the ABS warning light, traction problems, and that annoying jerky acceleration. In my case, it turned out to be a defective control unit in the ABS system, not just a sensor problem. My trusted workshop diagnosed it and had to replace the entire control unit. The repair set me back about 1000 Euro, but it completely solved the issue. Before offering more specific advice, could you tell us: Have you noticed any other warning lights? Does the problem get worse when you brake? Have you scanned for error codes? This info would help confirm if you're dealing with the same issue I had.

Had my car serviced just last month at 38842 KM, and I'm seeing similar symptoms to what you described. Yes, I'm getting additional warning lights, the traction control light flashes along with the ABS light. The braking definitely feels worse when I press the pedal hard, almost pulsating. Haven't scanned for codes yet since I don't have access to a BMW diagnostic tool. That's quite concerning about the control unit cost. I was hoping it would just be a sensor issue. Did you try cleaning the sensors before replacing the whole unit? Also, did you notice any correlation with weather conditions? The problem seems more noticeable on cold starts.

Hey again! Thanks for the follow-up. Yes, I remember trying everything before going for the full control unit replacement on my 5 Series. Actually, I did try cleaning the sensors, got under the car and cleaned all four wheel sensors thoroughly. Even tried using electrical contact cleaner, but it didn't solve the issue. About the cold starts, yes! That's exactly what made it tricky to diagnose at first. The problem was definitely more pronounced during cold weather, especially first thing in the morning. I initially thought it might just be moisture affecting the sensors, but the symptoms persisted even after everything dried out. The pulsating brake pedal you're describing is exactly what I experienced too. It's like the ABS is engaging when it shouldn't, right? That's what really convinced my mechanic it wasn't just a sensor issue, the control unit was misinterpreting the signals and triggering the ABS out of nowhere. Look, I know the control unit cost is steep, but honestly, trying to fix it with half measures might just waste more money in the long run. My advice would be to get it properly diagnosed with a BMW diagnostic tool first. Most good independent workshops have them now, so you don't necessarily need to go to the dealer. Have you noticed if the problem gets better after the car's been running for a while? That might help confirm if we're dealing with the same issue.

Thanks so much for the detailed response. You've basically described my situation perfectly. Yeah, the problem does improve slightly after the car warms up, but it never completely goes away. The pulsating is exactly as you described, feels like the ABS is kicking in at unusual moments. I guess I'll have to bite the bullet and get it properly diagnosed. You're right about not wanting to waste money on partial fixes. I was just hoping to avoid that big repair bill, but safety comes first, especially with these symptoms. I'll look for a reputable independent workshop with BMW diagnostic capabilities, should be a bit cheaper than the dealer at least. Really appreciate you sharing your experience. It's helped me understand what I might be dealing with. I'll probably get it checked out this week before it gets any worse. Will update the thread once I know what's actually wrong with it.