BMW Z4 Hands-Free Calling Dead, Microphone Mystery

Hey there! I had a similar issue with my 2018 BMW M4 last year (I have some experience working on cars but mostly basic maintenance stuff). The symptoms were exactly the same, complete failure of the hands-free system with an error showing up. Took it to my workshop and turns out the entire infotainment control unit was faulty. Cost me around 815 Euro to get it replaced, but it's been working perfectly since then. What's the exact error code you're getting? Also, did you notice any other weird behavior with the radio or navigation before this happened? Knowing these details would help determine if you're facing the same issue I had. PS, My with a BMW X3 from the same year had similar problems, so it might be a common issue with that generation's infotainment system.

Thanks for sharing your experience! My vehicle just hit 27414 KM and had its latest service last month, so this issue caught me off guard. The error code I'm getting is 2A4D-B1, and actually, now that you mention it, I did notice the radio volume would occasionally fluctuate on its own about a week before the hands-free system failed. Really hoping it's just the microphone and not the entire control unit. The service advisor mentioned something about checking the wiring harness first, but I'm starting to think it might be more serious based on what happened with your M4. Did your radio show any quirks before the complete failure?

Hey again! Thanks for providing those details, that error code and the radio issue sound very familiar. Yeah, my M4 definitely showed similar symptoms before the complete failure. The unusual volume fluctuations were actually one of the first signs I noticed too. When my system first started acting up, I was also hoping it was just the microphone or a loose connection somewhere. The workshop initially checked the wiring harness on my car too (which makes sense as it's the cheaper fix), but they found everything was properly connected. With your Z4 showing the same pattern as my M4 did, the volume fluctuations followed by the hands-free failure, I hate to say it, but it's looking more and more like a control unit issue. The 2A4D-B1 error code is actually the same one I had. One thing I learned from my experience is that these control units tend to deteriorate gradually before completely failing. The good news is that once it's replaced, it should solve all these issues completely. My M4 hasn't had a single problem with the infotainment system since the replacement. It's a bit pricey, but at least it's a permanent fix rather than a band-aid solution. Let me know what your workshop finds out. I'm curious to see if it ends up being the same issue!

Thanks so much for all this detail, it's really helpful to have someone who's been through the same thing! I was afraid you'd say that about the control unit. Those volume fluctuations matching your experience pretty much confirms my worst fears. At least now I won't waste time and money trying smaller fixes first. I've got the car booked in next week for diagnosis, but I'll definitely mention your experience to them. Guess I better prepare myself for that 800+ euro hit to my wallet! It's frustrating since the car isn't even that old, but like you said, at least it should be a permanent fix. Really appreciate you taking the time to share your experience, saved me a lot of headache trying to figure this out. I'll probably just have to bite the bullet and get the whole unit replaced. I'll definitely keep you posted on what they find. Thanks again for all your help!