DDEC X DD15 625 FMI 14

[ktblogistics]

check your cpc modules , got white or yellow labels , some have 250k and 500k baud rate, so truck will start but not work correctly, i would bet on bad cpc as i had replaced around 50 of them, truck is manual or auto? if truck starts your can line should be ok, ohm diagnostic port on can bus with key of to see if you have 60ohms, maybe missing resistor,
or with dddl at cylinder cutout you can adjust rpm manually see if this works , it would confirm you can command mcm to raise rpm