For those that may come across this years later like I did, just took my 2020 Bolt to a drive thru car wash without issue. Only thing different from any previous cars, I had to put the car in park and then neutral. Official directions are in the owner's manual. It's easier to lookup the pdf so that you can just ctrl-f search for car wash mode. Search feature in the myChevrolet app didn't find it. Pg 191-192 in the 2020 manual. Posted here because it was the first Google search result. Hope this helps.