Just happened to my new 2017!
Just happened to my new 2017! Only had truck since Saturday & it was extremely easy to change gears(prnd) then today it would not drop to reverse, like op said P flashed. Shut off, tried several times, look over All display panel, no idiot lights etc. Thought maybe a door was ajar?? Even though no indicators on, open shut front & rear doors, tried again & slight force(which I had done before)& it started. No idea!?