I'm digging through search results, and will probably find the answer eventually, but anyone have a quick answer...
I have a used ECM from another truck that I've run the replace and reprogram ECU function on, so it has the correct VIN for my truck (2009 Sierra)
I also have a new TDM.
When I put in and turn the key, the security light just stays on.
Checking tech2 (clone), it says Key Valid: No (amongst a bunch of other things)
Do I need to buy a brand new master key for the truck before I can proceed, or can I use this one?
Do I need to syn