Truck Repair: cummins no start, key switch, pin connector

Question
I have a  m11 cummins I beleave its an isb it has ben completely out of framed no more than 60 days ago and put back in service  now it has a no start condition  a road mechanic has been trying with no success to repair it  running diagnostics  on it shows no codes and no history  fuel pump is working with good psi  all interfacing connections are clean and secure i am going to look at it next and want any insight you might have

Answer
Will the Electronic diagnostic machine "talk" to the engine ECM?If so that rules out unswitched battery wiring.Next check pin A on the round 23 pin connector for key switch voltage.Then check EPS sensor mounted in the frt gear cover next to the accy drive.Should have between 1000-2000 ohmns.I would get a 11/16 wrench & remove it to check it to make sure the plastic is not protruding past the metal case,if so replace it.