My friend's 2004 Civic Value Package suddenly started having what I think are some electrical problems, they started when the tensioner bolt for the alternator and AC belt broke. 1st gear won't fully engage (almost feels like neutral, revs and barely moves), and 4th/overdrive doesn't come on either. The AC doesn't get cold (it worked great before the bolt broke), and the temperature gauge is inop. MIL is on, but I couldn't get any communication through the DLC.
I'm thinking something with the Multiplex Control Unit, because I can't think of what else could cause all these problems.

Anyone else have a similar issue? Could the issue with the tensioner have somehow caused it?