I think that it has to do something with the ULF module. I had a first generation module and the volume was just fine. I do have the later microphone. As I said earlier, the person on the other end can hear me just fine even with one of the windows rolled down. I replaced it with a 13th generation module for the Iphone. I had issues with connectivity but that ended up being what was in the contact list. Anyway, does anyone else have any idea?

Thanks....

PS. I can not take mine to the dealer because 2001 X5 is not supported for bluetooth.