yep, usually bad connections, unless someone was hacking and slashing in there.
Chrysler Collision Detection (CCD) Bus is how the computers (PCM,CAB {ABS}, BCM, IPC) 'talk' to each other. High speed 'blips' of voltage over a party line, with each computer picking up the signals meant for it.
You will probably get confused the first few times through the manual. The BCM one is usually the one with Communication codes.
Buried in the first few pages is the sentence (paraphrasing here) "Codes with an * (asterisk) in front of them are customer complaints."
Like a customer is going to complain that the IPC is not getting a Bus signal!
Anyway, try to pull codes and get a realistic trouble shooting chart to start with.
BTW, if the (for example) Instrument Panel Cluster (IPC) is not communicating with the other modules, the OTHER modules wil report the lack of communication, NOT the IPC (It's not talking, remember?)