Disconnetcting the encoder will not clear this fault ive had a few probs with this code
How many hours has the truck done????
Check the cables to the steer motor if yo uhave a break this will throw this error
Check that the small gearbox on the bottom of the mototr hasnt siezed I have had lots of problems with these
It could also be a faulty controller i have seen this on a couple of occasions
Hope this helps