They check the ECM versions for any deletes you have a idea on how we can delete and how they could not detect they give you a few deletes that do not pertain to emissions for that emission year model
I have the manual for the emissions telling what is allowable and what is not, CA does the same crap it bleed over to AZ a few years back when LA moved here just certain shops that can do emissions on diesels most are truck dealers and dumb as a box of rocks one told Mike he was going to need testing on a 8v71 before he could plate it.
Just 3 counties in AZ have emissions testing and he lives in one no test no plates, I live in one that doesn't have the testing lot of people live at my address lol even Don Fairchild
The ECM calls for EGR operation between a range of RPMs, say 1200 to 2000 RPM. That can be raised to say, 3900 to 4900 RPM then it's unlikely the engine will ever rev high enough to call for EGR operation, I mean really unlikely. Nothing is actually deleted. I don't know we could try it.