BMW iX2 Alarm Failure: Dead Auxiliary Battery Alert

Hey there! I had a similar issue with my 2021 BMW iX3 last month. The auxiliary battery was indeed the culprit, it's a common problem when these batteries age, even with relatively low mileage. The symptoms were exactly like yours: non-responsive alarm system and error codes popping up. Got it checked at the garage, and they confirmed the auxiliary battery had degraded significantly. It's a separate unit from the main EV battery, specifically powering the alarm system and some other auxiliary functions. The fix wasn't overly complex, just needed a battery replacement and a system reset. This isn't a major mechanical issue, but it's definitely something you want to address soon to keep your security system functional. The whole service took about two hours. Make sure whoever works on it has experience with BMW electric vehicles, as they need specific diagnostic tools to properly reset the system after replacement. Best of luck getting it sorted.

Hey, thanks for sharing your experience! I'm relieved to hear it was just the auxiliary battery, sounds like exactly what I'm dealing with. Would you mind telling me roughly how much you ended up paying for the fix? Also, just curious if you've had any other issues pop up since getting it sorted? Really appreciate the help!

Hey again! Just wanted to follow up, after seeing the mechanic, everything's working perfectly now! The total cost was 330 € to fix the battery discharge issue. Honestly, it was worth every penny because the alarm system's been rock solid since then. Haven't had a single problem or error message pop up in the past weeks. The additional battery alarm system defective warning is completely gone too. It's such a relief not having to worry about those annoying error messages anymore. The car feels just like new! I know 330 € might sound a bit steep for a battery issue, but considering it's a specialized job for an EV and includes all the diagnostic work plus system reset, I'd say it's reasonable. The peace of mind is definitely worth it. Hope this helps with your decision-making! Let me know if you need any other info about the repair.

Thanks so much for the detailed follow-up! I actually just got back from getting mine fixed and had a pretty similar experience. Took your advice about finding someone who knows EVs, and I'm glad I did. My repair came in at about 350 €, so pretty close to what you paid. The mechanic I found was really thorough, explained everything about the auxiliary battery and even showed me what was causing the issue. They had it done in about two hours, just like you mentioned. The whole system's working perfectly now, tested the alarm a few times just to be sure! Funny thing is, I was stressing so much about this, but it turned out to be a pretty straightforward fix. Thanks again for helping me out with your experience, saved me a lot of worry and probably some money too by knowing what to expect. Really appreciate you taking the time to share all the details! Best decision I've made was getting it sorted right away instead of waiting. Guess that's one less thing to worry about now!