What all do I need to get diag software for our trucks?

Hello, our lead "mechanic" has scared our boss away from buying a laptop and diag software because of how expensive it can get, but we have spent thousands of dollars on four trucks at the dealerships that I am almost certain I could've prevented had we spent $2500-3500 on the diag software for these trucks and just made it a single trip or I fix it myself.

My question today is this, I have not had to get all the equipment before to self diag and buy the diagnostic programs for these rigs before. We have two 2010 Internationals with Cummins ISM motors, and two Sterlings with Series 60 Detroits.

What all would I need for these trucks?

I imagine a Laptop, a Detroit Diesel Diagnostic Link, a 6 pin to USB connector or something similar? I don't know what Cummins uses.

Also, is there a a version or a way to make a 12 month license permanent or something? Cause $500-1000 a year will definitely scare my boss lol

We keep having issues with the Detroits especially, check engine lights and whatnot, but half the time if they aren't on when Freightliner gets to them it's a non issue so we waste money on that too. Also would like being able to change parameters, add a little fuel, etc to liven the Detroits a bit.

Thank you!

 

More like my boss doesn’t know anything about trucks but the owner of the company is a cheap guy so bossman is scared by our “mechanic”