This is from Painless:
The cummins ECM does not have a check engine light driver. The check engine lights on '03+ Dodge trucks are controlled though either a Chrysler Collision Detection Network CCD+/- or a Programable Communications Interface databus depending on the year of the truck.
Since the Second Gens don't have the instrument cluster with that type of communication protocol, you would have to rely on a diagnostic trouble code scanner to recgonize or diagnose any problems with the engine.