BMW iX3 Jerking and Power Loss: Troubleshooting Help

Hi! I had a similar issue with my 2020 BMW iX4 (and previously owned an i4). I have some experience working on EVs, though I mainly rely on professional help for serious issues. Your symptoms sound exactly like what I dealt with, the jerking and power loss were quite concerning. Turned out it was a messed up chip tune from a third-party shop. My regular workshop found that the non-original programming was causing conflicts with the vehicle's systems. They had to reset everything to factory settings and do a proper recalibration. Cost me about 180 Euro but totally worth it, car runs perfectly now. Before I can give more specific advice, could you share: Have you had any recent modifications or tuning done? Which fault codes are you seeing? When did these symptoms first appear? Feel free to share more details so I can help better!

Really appreciate the detailed response. My iX3 just hit 98303 KM and had its latest service two months ago. Haven't done any mods or tuning, keeping everything stock. The issues started about a week ago, showing fault code P0A7F. Initially thought it might be related to the recent firmware update, but the symptoms are getting worse. The jerking is most noticeable when I'm at around 30% battery level. Good to hear yours was fixed with a reset. I'll definitely mention this to my mechanic when I take it in next week. Thanks again for sharing your experience!

Hi! Thanks for the additional details, especially about the P0A7F code. Actually, after sharing my previous experience with the chip tune issue, I had another similar episode with my iX4 that sounds more like what you're describing. The jerking at 30% battery level is a telltale sign, had the exact same thing happen to me. In my case, it turned out to be a faulty battery management system (BMS) sensor. The P0A7F code typically points to issues with the hybrid/EV battery system, which matches what I experienced. When I took it to the workshop, they found that one of the voltage sensors was sending incorrect readings to the BMS, causing the system to limit power output as a safety measure. The jerking was happening because the car was constantly trying to adjust power delivery based on these wrong readings. The fix wasn't too complicated, they replaced the faulty sensor and recalibrated the BMS. Cost was higher than my previous repair, around 400-500 in total, but the car's been running smoothly since then. Let me know what your mechanic says next week. Based on the similarities, I'd bet it's either the BMS or one of its sensors.

Thanks so much for your help! Just got back from the mechanic and you were spot on! They found a faulty voltage sensor in the BMS that was causing all the issues. The repair cost was actually a bit less than what you paid, around 350 total for parts and labor. They replaced the sensor, recalibrated everything, and the car's running like new again. The jerking is completely gone and power delivery is smooth, even when the battery gets low. Really glad I mentioned your experience to them, helped them diagnose the problem much faster. Definitely learned my lesson about getting these symptoms checked out quickly. Thanks again for sharing your knowledge, really helped me understand what was going on with my iX3!