Cummins isx headache

[Chamberpains]

Okay, just so we're clear, when you reach the speed of the 68 to 69 miles per hour you get the red shut down engine light on the dash? Has the truck physically shut down on you?You pull over shut the truck off restart it then take off again now you get the red engine shutdown light at 1500 RPMs and above. Does it happen through every gear? Does it come back on at a certain speed? What kind of shop did you take it to? It's odd that the shut down light would come on and it wouldn't log a code of any sort. Did they check it with Cummins Insite or did they use a generic code reader?
Does the truck run good all the time? Including when the light comes on?