the truck has thown a CEL and I am trying to get the code so i can fix it. I have tried 2 different readers and both have the same result nothing. This is kind of discerning as i have only had the truck for 3 months. The only thing i have added was Cruise Control, and a Viper 5101 remote start since i have added the truck. I have checked the fuses and all show good with a multimeter, Does anyone have any idea what may cause the port not to work? Any help will be appreciated. Thank you.