It may not be a problem at all. If you just cleared codes out of the ecu, that code can be present until the truck "self checks" everything. If thats not a case, you probably do have the can/bus error. Not very hard to fix, maybe 45 minutes tops. You will have to remove the instrument cluster completely. Once out, look inside the dash to the left side on the back of the horizontal brace. There is a major ground connection back there. Remove the screw holding it ot the brace, sand the area a bit, then reconnect and reassemble.