Hi there. Welcome to our site!
PLEASE READ THIS FIRST:
I’m a retired master technician and tech instructor with over 30 years experience. However, if you’re thinking on working on the vehicle yourself, all my knowledge and resources won’t help if you…
… don’t have tools or the skills to use them
… don’t know there will probably be some special tools and equipment needed for a proper diagnosis
… don’t realize it may take a few back and forth replies to solve the issue
… don’t understand that I will need you to provide specific information
Perhaps I can help, but to do so I'd need additional information from you:
First, I need to know what exactly is it that we're working on; 5.9L diesel or 5.7L gasoline? Auto or std trans? Electronic or manual transfer case circuit?
Second, we need to see if there's something wrong with the CAN BUS. To that effect, can you communicate with any of the modules using the Starscan? If so, can you see if the TIPM is supplying 5 volt reference to the shift motor/mode sensor assembly?