DO NOT FOLOW what some are telling you to do. If you do you are taking a chance of causing damage to your Jeep.
I have a 2014 GC and I followed the instructions exactly like they say and it works fine. The only place you are is were it tells you that it must be in Park to shut off in the readout. Just continue holding the Start/Stop button and it well after a few moments shut the engine off.
Then when you restart the engine you well see that it has indeed put the trans into Park just like they stated.
Again don't force it into Park like some have suggested. That may work for other models but is not the way yours is intended to operate.
I followed the instructions as the book stated and they do work. The one thing they should tell us is to continue holding the Start/Stop button till the engine shuts down.
Hope this helps.