Bought a 2021 GMC Sierra (10-speed) truck from ClearShift Dealer in Highlands Ranch, 20K+ miles, immediately after delivery the engine light came on. Still under power train warranty. Dealer said it went into limp mode because it was learning a new driver. Dealer cleared code. He then went to Elway Dealer who said he needs a new Valve Control Body or a new transmission but the parts are on national backorder.