BMW X4 Alarm System Dead, Quick Fix or Major Issue?

Hey there! I actually faced a similar issue with my 2017 BMW X3 last month. The alarm system gave up completely, and the diagnostic showed it was indeed the backup battery. These backup batteries typically last 3-4 years, so this is pretty common and nothing too serious. My mechanic found that the old battery had actually started leaking a bit, which affected some of the surrounding connections. They had to clean up the contacts and replace the battery unit. While they were at it, they also checked the main battery's health since these systems are interconnected. The whole repair was pretty straightforward, took about an hour. Just make sure whoever works on it uses an OEM battery unit rather than aftermarket parts. Also, have them check the main battery's charging system while they're at it, as a failing charging system can sometimes cause the backup battery to drain faster than normal. Hope this helps with your decision!

Hey, thanks for sharing your experience! It's really helpful to know that you went through something similar. I'm actually about to take my X4 to a shop later this week. Just curious, do you remember roughly how much you ended up paying for the whole repair? Also, has everything been working fine since they fixed it, or have you noticed any other quirks with the alarm system?

Hey again! Great news, I can give you a full update since my repair! After getting it fixed, everything has been working perfectly smooth. The total bill came to 330 € for replacing that aging battery, and honestly, it was money well spent. The best part is that pesky "Additional battery alarm system defective" warning has completely disappeared from my dash. It's such a relief not having that pop up anymore! The alarm system now arms properly every time I lock the car, you know that reassuring beep we all love to hear? Trust me, once they fix it, you'll wonder why you waited so long. I've had zero issues since the repair, and my X3's security system is working exactly like it did when the car was new. Just make sure they do a full system check after the replacement, that's what my mechanic did, and it really gave me peace of mind. Let me know how it goes with your X4! Always happy to compare notes with fellow BMW owners.

Thanks for sharing all those details! Just got back from the shop today and wanted to update you. You were absolutely right, it was indeed the backup battery. The repair was pretty simple and cost me about the same as yours. The funny part was when I got there, my usual mechanic was off sick, and I actually got someone much better! The new guy walked me through everything he was doing and even showed me where the backup battery was located. He cleaned up all the connections too, which apparently needed some attention. The whole thing took less than an hour, and now my alarm system is working perfectly. That annoying warning light is finally gone, and I get that satisfying beep every time I lock the car. Guess I was worried over nothing! Really appreciate your help in pushing me to get this sorted. It's such a relief to have a properly functioning security system again. Sometimes it just takes someone else's experience to give you that needed confidence to get things fixed!