I have the same problem with my 2016 Sierra . I watched a u-tube video on how to reset the computer & clear the 4x4 service light . I followed the instructions & got it working ! Of course I didn't write down the procedure & now I can't find the video ! Now that I see what issues other people are having ; I can see where I'm going wrong . Apparently you MUST shift to 2 wheel drive BEFORE you shut the truck off !! Talk about stupidity !! If & when I get this system reset I will definitely pay attention ! Thank you for all the great info !
