Battery Short randomly losing ECM power w/ign on

[Gump12b]

Called dealership I bought the ecm from, of course they want the truck before they can verify the ecm is bad. Same thing at Cummins but I talked the service manager into letting me bring them the ecm and put it on their bench cal and see if they have the same issue as me with it losing power, they also want the original one to try it out. They claim they want to make sure they can get the right parameters off for a new ecm if they confirm that’s the issue.

Main worry is with truck being demandated will they see the different tune? I have not personally tuned one I’ve only had unilevers do the programming. Should I be worried about the seeing the tube or should I consider taking my truck to them?