A:AnswerUnfortunately, it will probably not work until you get rid of the engine codes. These systems are generally designed to not start your vehicle if it has a CEL.
A:AnswerAny numbers of things. Make sure you don't have engine codes. Make sure you don't have blown fuses.
I had a strange case where it stopped working after my battery died and I had to jump start it. The controller module needed to be reprogrammed to get it to work again. I called Idatalink and they confirmed it should continue to work after a dead battery so I'm not sure why that happened.