BMW M4 E-Call System Glitch, Battery or Bigger Issue?

I had a similar issue with my 2019 BMW M2 Competition last year. The emergency call system started acting weird and after diagnosis, it turned out the backup battery was completely discharged. The backup battery is separate from the main car battery and specifically powers the emergency call system. When I took it to the garage, they found that the battery had failed prematurely. It wasn't a major repair but definitely needed immediate attention since the emergency call system is a critical safety feature. The fix involved replacing the backup battery unit and recalibrating the emergency call system. They also had to clear the error codes with their diagnostic tool. The whole repair took about 2 hours. It's worth getting it checked soon because if the backup battery dies completely, the emergency call system won't work at all in case of an accident. Since then, no issues with the system, works perfectly fine. Make sure you go to someone who knows BMWs well, these systems can be tricky to diagnose properly.

Thanks for sharing your experience! That's really helpful to know it was the backup battery in your case. Makes me feel better about my diagnosis. Just curious, do you remember roughly how much you ended up paying for the whole repair? Also, no other electronic gremlins popped up since getting it fixed? Thinking about taking mine in next week and want to know what I'm getting into.

Hey again! Yeah, I can tell you exactly what I paid, it was 110 € for the complete fix, including the new backup battery, labor, and system recalibration. And I'm happy to report that since getting it sorted, everything's been working perfectly! The emergency call system is back to normal, and I haven't had a single electronic gremlin pop up. Actually, it's been about 8 months now since the repair, and it's all been smooth sailing. Getting it fixed was definitely worth it for the peace of mind. The mechanic told me it's pretty common for these backup batteries to need replacement, so you're not alone with this issue. When they checked mine, the battery was completely drained, just like yours seems to be. Good call on planning to take it in next week, better to get it sorted sooner rather than later. The repair itself was pretty straightforward once they diagnosed it. Hope this helps with what to expect!

Thanks so much for all those details! I bit the bullet and took my car to the mechanic yesterday. You were spot on, it was indeed the backup battery. The funny thing is, when I got there, the mechanic knew exactly what was wrong before even checking! Apparently, he'd fixed three other BMWs with the same issue just that month. The whole thing cost me about 120 bucks and took roughly two hours, just like you said. Watched them work on it through the shop window, way less dramatic than I expected after my previous mechanic horror stories! They even showed me the old battery and explained why it failed. Best part? The emergency call system's working perfectly now. Tested it right after leaving the shop and the response time is back to normal. Really glad I didn't put this off any longer. Thanks again for helping me avoid another sketchy repair experience!