Bingo. Same question I was going to ask.

OP- let us know. There are odd issues when the battery begins to fail on these cars...modules get spurious errors as all the handshaking that goes on can be interrupted. You'd think BMW would give you a "bad battery" warning but they dont. You can search here and BF for similar stories. One guy spent thousands with a dealer chasing nonsense, finally a $200 battery did the trick.