One of coworkers had a diesel class last week. The dot has made the manufactures put a new code in the engine modules that sets if you put a programmer or have someone tweak the engine program. This is starting in 2015 pickups. This is a latched code. Only the dot and the manufactures can read this code. The code will set in all modules in the vehicles. You can not clear the code. The dot will find it when you sell the truck and goes through emission inspection. Will make it unsellable. Depending how the manufacture scans for codes under warranty the info would be sent to manufacture and cancel the warranty. I know that the scanner I have to use at work for late model vehicles is linked with GM. To use the scanner I have to be on GM web sight.