"no bus" means the "bus"( used to let various modules communicate to each other and the PCM) is not working, could be a bad connection behind the cluster, or bad connector completely. i've heard there was a TSB for this problem, not 100% sure as I havnt had this problem.
if it were me, i'd pull the cluster and check all the connections behind it really well and make sure all the blades have good contact.
2005 TJ, Rockey Mountain Edition, 4.0, D44, 6-sp, Patriot Blue.
2002 Mustang GT 'Vert, 5-sp, not stock, Mineral Gray.
2001 Ranger XLT , 4.0, 5-sp, White.
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