[hatzie]

Originally Posted by kaycee

Another new one for me what is TIS

I used the wrong T acronym. TIS is Technical Information System.

I meant AC Delco TDS. https://www.acdelcotds.com/subscriptions
Delco sells a 24 month subscription to allow you to program modules in one vehicle with stock GM software and parameters for your VIN. It costs something but it's not so expensive that it makes going to a shop worth my time.

You need a J2534 pass through interface device that's supported by Delco TDS. The blue Bosch MDI, MDI II, or Vetronix Tech 2 are the dealership level tools. You can buy these from China and they will work. I have WiFi MDI and Tech 2 knockoffs. I figure most "real" Tech 2 handhelds are old enough to be on borrowed time and the 1st gen MDI is in the same category. My Chinese units will outlast my need for the tools.
The Green Bosch Mastertech VCI or VCI II are similar to the blue GM only units but they also support Ford among other manufacturers.
Autel and Snap On sell supported J2534 passthrough interfaces to go with their pro level diag tools but they cost a pretty penny. Decent shops are amortizing these $3,000-$4,000 tools over several vehicles.