BMW iX3: High-Voltage System Failures and Power Loss

Hi there! I have some experience working on EVs and went through something very similar with my 2020 BMW iX. My i4 hasn't given me these issues yet. When I had those exact symptoms, system errors, unusual shutdowns, and limited power, it turned out my high-voltage battery was severely discharged and partially defective. Took it to my regular workshop where they did a full diagnostic scan and battery health check. The repair cost me around 290 Euro to get it sorted. Before I can suggest more specifics, could you share: How many miles/km on your iX3? When did these symptoms first appear? Have you noticed any changes in your typical range lately? This info would help me determine if you're facing the same battery issue I had. Feel free to share any other symptoms too.

Thanks for the detailed reply! My iX3 has 80846 KM on the clock and just had its annual service last month. These issues started about a week ago, and yes, I've definitely noticed my range dropping by about 15-20% compared to normal. The weird thing is everything was working perfectly fine until these unusual shutdowns began. The battery indicator still shows normal charge levels, which makes me think it might be something else. Could be a faulty sensor or control module maybe? Really hope it's not the full battery pack having issues like in your case. Let me know your thoughts!

Hey again! Thanks for providing those extra details about your iX3. After reading about your range drop and the timing of these issues, I'm even more convinced it's similar to what I experienced. The tricky part is that my battery indicator was also showing normal levels when I had these problems, but it turned out to be misleading. The control module wasn't reading the actual battery state correctly. What really caught my attention in your case is that 15-20% range drop, that's almost exactly what I noticed before everything went downhill with mine. In my case, the workshop found that one of the battery modules was failing, causing the whole system to act up. The normal charge level display was basically a false reading because of a communication error between the battery management system and the faulty module. Since you mentioned your recent service, did they do a full battery diagnostic then? If not, I'd strongly recommend getting that checked specifically. Could save you from dealing with a complete shutdown like I had. My car literally left me stranded twice before I got it properly diagnosed. Would be interested to hear what your workshop finds. Keep us posted!

Thanks so much for sharing that in-depth experience! No, they didn't do a specific battery diagnostic during the service, just the standard checks. After what you've described, I'm definitely going to book it in for a full battery check ASAP. Really don't want to risk getting stranded, especially with these unusual shutdowns getting more frequent. The similar range drop and misleading battery readings you mentioned have me worried it could be the same issue. Will make an appointment first thing tomorrow and get this sorted. Thanks again for helping me narrow down the likely cause, it's given me a much clearer direction on what to tell the workshop to check. I'll update the thread once I know what they find!