My 2009 2500 with 6.7L keeps having the engine light come on . It isn't showing any code. I'm told that this has been a common problem for us in higher altitudes. We live at 8600 elev. The light seems to only come on as we leave the house and head for the highway which is somewhat lower. anyone have any ideas? I have been to the local dealer several times as this has been a problem almost within a year after I bought the truck. I am hoping someone out there has had a similar problem and got it resolved!! Thanks for any ideas!