BMW M4 GPS/Nav System Failures: What You Need to Know

I had the exact same problem on my 2015 BMW M3 last month. The symptoms matched yours perfectly, slow navigation, GPS signal drops, and error messages popping up. Took it to the dealership and they diagnosed a faulty GPS antenna module. Apparently, water had seeped in through a deteriorated seal around the shark fin antenna on the roof. The moisture corroded the connections inside. This was actually a serious issue because it wasn't just affecting navigation, it was also impacting the emergency call system and some connected services. They had to replace the entire antenna assembly and reseal everything. Not a DIY job since it required special diagnostic tools and programming. The repair took about 4 hours at the shop. Navigation works perfectly now and all the error codes are gone. I'd recommend getting it checked soon before more water damage occurs.

Thanks for sharing your experience! That's really helpful since it sounds exactly like what I'm dealing with. The water damage explanation makes total sense given the symptoms. Would you mind sharing what the repair ended up costing you? Also curious if you've had any other issues pop up since getting it fixed?

Hey there! Just wanted to follow up, since taking it to the mechanic last month, the GPS has been working flawlessly! The total repair came to 200 € which included replacing the antenna assembly and resealing everything. I'm really happy with how it turned out, no more signal drops or error messages, and the navigation is super quick now. Best of all, I haven't had a single issue since the repair. The emergency call system and connected features are all working perfectly too. Believe me, it's worth getting it fixed properly, makes such a difference having everything working as it should again. Definitely a relief to have it sorted!

Thanks so much for the detailed update! I actually just got my car back from the mechanic today and wanted to share how it went. The whole experience was better than expected after my last sketchy repair job. Got it diagnosed and fixed in one day, turns out you were spot on about the water damage to the antenna. They replaced the whole assembly and resealed everything properly. The final bill was pretty reasonable too, even included a system check and software update. The best part? The navigation is working perfectly now! No more waiting forever for routes to calculate or losing signal. Those annoying error messages are gone too. Such a relief to have it working properly again. Honestly wish I'd gotten it fixed sooner instead of putting it off. Thanks again for pointing me in the right direction with this, saved me a lot of headache!