Yeah, my wife's Tahoe has it, but it actually gives you an oil life percentage along the way, so you can see that it's actually working. Once it reaches 10%, it tells you that an oil change is needed. Usually comes up at about 7-8000 miles. Of course, the H3 ONLY alerts you when it's time to change the oil, so there's no real way to be sure that it's working. And if I go through the reset process BEFORE it has triggered, I have no way of knowing if it actually reset or not; it doesn't acknowledge a "reset" (perhaps that is different if it has triggered first?).