BMW i5 ABS Warning: Lateral Sensor Issue Discussion

Hey there! I have some experience with BMWs and their electrical systems. Had a similar issue with my 2022 BMW i4 last year (also own an i7). The ABS warning light drove me crazy! Took it to my trusted workshop where they diagnosed a defective control unit, exactly what you're describing. The whole repair, including parts and labor, set me back around 1000 Euro, but it fixed the problem completely. Haven't had any issues since. Could you share a bit more info about your i5? Like when did the warning light first appear, and are you noticing any other symptoms? Also, are you experiencing any stability issues while driving? This would help me understand if you're dealing with the same problem I had. Before heading to the workshop, make sure to get the exact error codes, it'll save you some diagnostic time and money.

Thanks for sharing your experience! My i5 just hit 154508 KM, and the warning light popped up right after my latest service two weeks ago. Not seeing any major stability issues while driving, but definitely feeling less confident without the ABS working properly. The error codes point to the lateral acceleration sensor, but I wanted to check here first before spending money on potentially unnecessary repairs. Your input about the control unit is really helpful, I'll make sure to have them check that too when I take it in. Did your ABS light come on suddenly, or was it flickering before staying on permanently?

Hey again! Thanks for the follow-up. Yeah, with my i4, the ABS light initially started flickering intermittently for about a week before staying on permanently. That's actually different from what you're describing, interesting that yours came on right after the service. Makes me wonder if something got knocked loose during the maintenance work. When my control unit failed, I also had perfectly normal stability in regular driving conditions, just like you're experiencing. The real issue only became apparent during harder braking. Have you tried any emergency braking tests in a safe area? That's when I first noticed something was definitely off with mine. Since you mentioned your error codes specifically point to the lateral acceleration sensor, that's worth investigating first. In my case, the initial diagnosis also suggested a sensor issue, but it turned out the control unit was sending faulty signals. The mechanics explained that these systems are pretty interconnected, so one component can make others look bad. Given your mileage is quite high (mine was only at 68000 km when this happened), it could really be either component. But considering the timing with your recent service, I'd definitely mention that to your mechanic. Could save some diagnostic time!

Thanks for that detailed explanation! No, I haven't done any emergency braking tests yet, honestly hadn't thought of that, but it makes total sense. I'll definitely try that in a safe spot this weekend. Really interesting that your initial diagnosis also pointed to a sensor issue before discovering it was the control unit. The timing with the service is definitely suspicious. I'll bring that up when I take it in tomorrow. They're a certified BMW workshop, so hopefully they'll be able to figure out if something got disturbed during the maintenance. I've documented all the symptoms and error codes, and your experience will help me ask the right questions. Thanks again for all the help, it's great to hear from someone who's dealt with something similar. I'll update once I get it sorted out!