also check for frame voltage
check you heavy negative power cable under the battery too
make sure its not touching the frame either rubbed through or corroded like Ed said

unplug the battery
with your DVM check resistance from the battery connector on the truck to the frame
you should read over a few megohms
any less id look at all of your heavy cables
also check the motor cables to the frame the same way
if you have regen you have to check A2 from the motor side of the RB contactor with the battery unplugged seeing its a normally open contactor

where in NY are you?
im on long island
if you need help email me
its in my profile (click my screename)

the 1 2 and 5 rec didnt have anything to do with this code
if they were bad youd get diff codes