http://www.faqs.org/qa/qa-12673.html"
no buS" means that your insturment cluster is not communicating with the onboard computer. Your cars have a "data
bus" the same as a personal computer. It is basically just part of the computers wiring system. Try checking plug in connectors in your wiring system. This could possibly be somewhere besides behind the instrument cluster, such as at the computer. Another thing to check is the ground system.
ON JEEP DODGE CHRYSLER VEHICLES COMPUTERS COMMUNICATE WITH ONE ANOTHER ACROSS THE "
BUS". THE
BUS IS CONTROLLED BY THE BODY CONTROLLER. DOUBLE CHECK ALL FUSES IN PDC (POWER DISTRABUTION CENTER) UNDER HOOD AND FUSE CENTER UNDER DASH. MAY NEED BODY CONTROLLER. "
NO BUS" MEANS PCM,BCM,TCM ALL COMPUTER MODULES ARE NOT COMMUNICATING WITH ONE ANOTHER.