Hope this fix works for you too. 2014 Silverado stuck in 4WD Auto (as indicated on the selector, but felt more like 4WD Hi while making U-Turns).
1. I switched the key to ON position (engine off) 2.Turned the knob to 2WD position, I pulled the connector marked J3 under dashboard (module close to the gas pedal)
3. The truck shifted to neutral by itself and seconds later the light on the knob was showing 2WD selected and voilà.
My connector was easy to pull and this maybe the source of my problems. Hope this helps.
Cheers!
