there are 2 drive systems that could be in this truck
EV100 or a cableform
based on the EV100 troubleshooting codes a -72 means the regen contactor is not picking up.
symptoms are:
Regen control does not operate.

POSSIBLE CAUSES
Open connection in the PA6 circuit.
- Check for open circuit or loose connection between
PA6 and the A2 connection of the RB contactor.
- Check for open circuit or loose connection between
7 REC and the A2 connection of the RB contactor

i doubt this is a cableform system because the fault codes are different.