BMW i4 ABS Warning Light, Lateral Sensor Malfunction?

Hey there! I've got some experience with EVs as I own a 2019 BMW iX3 (had a BMW i3 before that) and had a very similar issue last year. I'd say I have some experience with car maintenance, but I'm no pro. The symptoms you're describing sound exactly like what I dealt with. My ABS light came on suddenly and the whole system was dead. Took it to my regular workshop where they diagnosed a faulty ABS control unit. Ended up costing me around 1000 Euro to replace, but it fixed the problem completely. Before jumping to conclusions though, could you share: Have you noticed any other warning lights? Does it happen at specific speeds? Did you recently hit any deep potholes? This might help narrow down if it's the same issue I had or something else. Let me know these details and I'll try to help further!

Thanks for sharing your experience! I've got 50338 KM on my i4, and it had its last service just two months ago. The ABS warning is definitely concerning, and I'm really hoping it won't be as expensive as your repair. To answer your questions, no other warning lights have shown up, and it seems to happen out of nowhere regardless of speed. Haven't hit any major potholes lately either. The car's been running perfectly fine otherwise. I'll probably have to take it to a shop to get it properly diagnosed, but wanted to check here first to get an idea of what I might be dealing with. Your input about the ABS control unit is really helpful, at least I know what to expect if that turns out to be the issue.

Hey again! Yeah, those symptoms do sound quite different from what I experienced with my iX3 now that you've provided more details. When my ABS control unit failed, I actually had the traction control light come on simultaneously, and it was pretty consistent at lower speeds. Since you're not seeing any other warning lights and it's happening out of nowhere, I'm starting to think it might actually be the lateral acceleration sensor like you initially suspected. Now that I think about it, my colleague had a similar unusual ABS warning issue with his i4, and it turned out to be exactly that, the lateral acceleration sensor was playing up. The good news is that replacing a sensor should be considerably cheaper than what I paid for the ABS control unit replacement. Based on what I've learned from my experiences with BMWs, these sensors typically cost around 200-300 Euro including labor, so much less painful for the wallet! Quick tip though, make sure whoever checks it does a proper diagnostic scan. When I had my ABS issues, the first shop I went to just cleared the error code without properly investigating the root cause, and obviously, the problem came back a week later. Keep us posted on what you find out. I'm really curious to know if it turns out to be the sensor after all!

Really appreciate the detailed follow-up! That's actually quite reassuring to hear about your colleague's i4 having the same unusual ABS warning issue. The fact that it was indeed the lateral acceleration sensor makes me feel better about my initial suspicion. And honestly, I'm quite relieved to hear it might only cost 200-300 Euro, that's way more manageable than what you had to pay for your control unit! Thanks for the tip about the diagnostic scan too. I'll definitely make sure they do a proper investigation rather than just clearing the code. I've got an appointment booked with a BMW specialist for tomorrow morning, so I'll get it properly checked out. Will update the thread once I know what's actually causing it. Really glad I asked here first, at least now I won't walk into the shop completely clueless about what might be wrong!