Ok, I know things were too good to be true... I got my first Check engine light but No codes. A quick trip to the dealer and it turns out the sensor on the upstream side of the cat was all sooted up. The shop Tec says that you use only compressed air to clean it. also cleaned the down stream sensor. Figures I ran reg diesel not my B20 that I normally run and it soots up my sensors. . Lol I guess these newer trucks are a learning experience. So add that to the maintance list clean the Cat sensors around 20,000 miles.....