Transmission Issue

[Mfield]

New to the forum. I drive a 2015 with the 5.3l 6 speed auto that started acting up on me yesterday. Came to a stop on a red light in rush hour traffic and the check engine light came on. Wasn't flashing and hill start braking assist was displayed. When the light turned green and i stepped on accelerator nothing happened. I dropped it into manual and stepped on the gas and the truck slowly started rolling, almost like it was starting in 4th gear. I got it pulled over and shut it down. Started it back up again, put it in Drive and the "D" started blinking. Check engine light was still on. After waiting and reading owners manual trying to figure out what was going on, the truck started and drove fine. Engine light still on steady. Took it to the dealer this morning, no engine light, truck ran fine. They are running diagnostics on it today. Anybody have a clue as to whats going on? I know it's a computer issue but not sure what it's doing. And the flashing "D", any ideas? The service valet guy didn't know but that's cool.  

[Crstfr]

never heard of the D blinking.. thats odd... .. hope they figure it out!

[Lgetz]

Have you checked your battery to see if it is good?  My truck only displayed longer cranking time when the battery gave up and had to boost truck once or twice.  Others have reported gremlins similar to your issues when their battery went out.  My original only lasted 2 years and 2 months.