Is this the SRS malfunction warning? Part of the SRS system is a pyro that blows the battery clamp off in case of an accident. There's a sensor on the battery clamp that will cause a SRS fault if the wire is loose, or has a problem. Once the code is set, it will show up even if the problem no longer exists. It is possible that you jarred the connection while replacing the battery and set the code. You'll need a rest from the dealer, a BavTech tool, or INPA and a K+D-Can cable.
See my reply in this thread:
http://www.e90post.com/forums/showthread.php?t=458022
and this thread:
http://www.e90post.com/forums/showthread.php?t=383433