if display is showing event code 32 this is 'line contactor not opening due to bad driver or welded tips'.

check contactor tips for welded together
if not welded: check voltage of the main coil by probing CA404-17 with the battery connected and key switch on, using B- on the controller for the negative reference. Handle should be up.
If voltage is less than 20v with handle up check harness for shorted wire to battery negative or short fo frame on wire 5904.
If wire is shorted fix wire.
If OK then check line contactor to ensure that the contactor is not stuck shut.
If contactor is not stuck shut and condition persists replace controller with known good controller. Ensure that the controller is programmed for the truck as described in the M4 tune up section of the service manual.