I had trouble with mine on a trip 2 years ago and tried to get one from Cummins in Las Vegas also, they couldn't find the part number. Ended up at a Cummins shop outside Redding,CA on the way home, they were very helpful and ordered me one to pick uip the next morning in Oregon.
Part number 3621094 is correct but Cummins doesn't call it a Throttle Position Sensor, they call it a "Sensor,Throttle" you would think the computer could find it either way but it can't.
They are way cheaper than the Mopar dealer.
Hope this helps,
Caleb