See, I learn something new every day. I was going off of what @wjburken was saying and I bet he knows what you just said but was generalizing. He said 2007 and 2008 knowing that they were not activated with the ECM software and he said 2009 Denali that did not have it at all. I have no experience with that engine because I was out of the shops by then and did not know the details you just shared. My bad.