I have a customer that had the "no bus" come in. From a few previous experiences I unhooked his ABS module, went key on, and plugged it back in. To this day it's never gone "no bus" again. Believe that was a 2000 CTD with 4WAL brakes. I've also run into clusters (which is a "module") that have had internal issues. Another one on the gas trucks and some Jeeps with JTEC that could cause alot of grief was the crank shaft sensor could short taking down the BUS.