BMW iX Alarm System Dead: Battery vs Control Unit Issue

Hey there! I have some experience with EVs and their electrical systems. Had a similar issue with my 2021 BMW i4 last year (also own a BMW iX3). The alarm system completely failed, and it turned out to be the auxiliary battery that was toast. These auxiliary batteries tend to wear out faster than expected in EVs, especially if the car frequently sits unused for longer periods. My workshop diagnosed it quickly, the battery had lost most of its capacity due to aging, even though the car wasn't that old. The fix wasn't complicated but wasn't cheap either, cost me around 330 Euro for the battery replacement and system reset. Since then, no issues at all. What's your mileage and how often do you drive the car? Also, have you noticed any other electrical quirks before the alarm system failed? This info would help figure out if you're dealing with the same issue I had.

Hey there! I have some experience with EVs and their electrical systems. Had a similar issue with my 2021 BMW i4 last year (also own a BMW iX3). The alarm system completely failed, and it turned out to be the auxiliary battery that was toast. These auxiliary batteries tend to wear out faster than expected in EVs, especially if the car frequently sits unused for longer periods. My workshop diagnosed it quickly, the battery had lost most of its capacity due to aging, even though the car wasn't that old. The fix wasn't complicated but wasn't cheap either, cost me around 330 Euro for the battery replacement and system reset. Since then, no issues at all. What's your mileage and how often do you drive the car? Also, have you noticed any other electrical quirks before the alarm system failed? This info would help figure out if you're dealing with the same issue I had.

Thanks for sharing your experience! I've got 94023 KM on the clock since my last service, and I've noticed some other small quirks lately. The central locking has been acting up occasionally, making a strange clicking sound before engaging. Definitely sounds similar to your situation with the auxiliary battery. I'll get it checked out at the workshop soon, better safe than sorry with these electrical gremlins. Good to know the fix wasn't too complicated, even if it's a bit pricey.

Thanks for sharing your experience! I've got 94023 KM on the clock since my last service, and I've noticed some other small quirks lately. The central locking has been acting up occasionally, making a strange clicking sound before engaging. Definitely sounds similar to your situation with the auxiliary battery. I'll get it checked out at the workshop soon, better safe than sorry with these electrical gremlins. Good to know the fix wasn't too complicated, even if it's a bit pricey.

Hey again! Back to add more details based on my experience. Yeah, that clicking sound from your central locking system is exactly what I experienced before my auxiliary battery completely gave up. It's like a telltale sign, the system struggling to get enough power to operate smoothly. Just a heads up, when I had mine fixed, they also recommended checking the wiring connections while they were at it. Turned out there was some minor corrosion on one of the terminals that they cleaned up. Might be worth asking them to do the same for yours, especially with that mileage. The price I mentioned earlier (330 Euro) included that extra check, by the way. But honestly, it was worth every penny because it prevented potential issues down the line. Since you're experiencing similar symptoms to what I had, I'd bet you're looking at the same repair. One thing I learned, after the replacement, I started using my car more regularly for short trips, not just long hauls. Seems to help keep the auxiliary battery in better shape. Maybe worth considering if you tend to leave your car sitting for longer periods? Let me know how it goes after the workshop visit. Curious to see if it's the same issue as mine!

Hey again! Back to add more details based on my experience. Yeah, that clicking sound from your central locking system is exactly what I experienced before my auxiliary battery completely gave up. It's like a telltale sign, the system struggling to get enough power to operate smoothly. Just a heads up, when I had mine fixed, they also recommended checking the wiring connections while they were at it. Turned out there was some minor corrosion on one of the terminals that they cleaned up. Might be worth asking them to do the same for yours, especially with that mileage. The price I mentioned earlier (330 Euro) included that extra check, by the way. But honestly, it was worth every penny because it prevented potential issues down the line. Since you're experiencing similar symptoms to what I had, I'd bet you're looking at the same repair. One thing I learned, after the replacement, I started using my car more regularly for short trips, not just long hauls. Seems to help keep the auxiliary battery in better shape. Maybe worth considering if you tend to leave your car sitting for longer periods? Let me know how it goes after the workshop visit. Curious to see if it's the same issue as mine!

Really appreciate the detailed follow-up! You're reading my mind about the car usage, I do tend to leave it parked for extended periods while traveling for work. That clicking noise matches exactly what you described. I've actually booked a workshop appointment for next week, and I'll definitely ask them to check those wiring connections you mentioned. The price doesn't sound too bad considering all the potential issues it could prevent. Thanks for the tip about regular short trips too, makes total sense for maintaining battery health. I'll try to incorporate more frequent drives into my routine. The whole thing's been a bit stressful, but hearing about your successful fix makes me feel much better about getting it sorted. I'll shoot you a message after the workshop visit to let you know what they find!

Really appreciate the detailed follow-up! You're reading my mind about the car usage, I do tend to leave it parked for extended periods while traveling for work. That clicking noise matches exactly what you described. I've actually booked a workshop appointment for next week, and I'll definitely ask them to check those wiring connections you mentioned. The price doesn't sound too bad considering all the potential issues it could prevent. Thanks for the tip about regular short trips too, makes total sense for maintaining battery health. I'll try to incorporate more frequent drives into my routine. The whole thing's been a bit stressful, but hearing about your successful fix makes me feel much better about getting it sorted. I'll shoot you a message after the workshop visit to let you know what they find!