Hi my name is Hal.
You need a scan tool that is capable of reading all power train codes not just engine codes. There is a trouble code stored in the TCCM ( transfer case control module)
If the service 4 wd message displays.
The code will tell exactly what is going on, and needed to make a diagnosis. Power train warranty on this vehicle is 5 yr 100,000 miles.
It will deal with the components that shift the transfer case, switch, TCCM module, shift actuator .
I recommend taking to the dealer to be diagnosed, for this repair is likely to still be covered under power train warranty. Check with dealer for covered components.
If you need more information PLEASE ASK a follow up question.
Thank you Hal.