22sierra3.0Elevation

2022 GMC sierra elevation with 3.0l diesel. picked up April 2022 1000 miles, emissions code appeared. Took it to the shop and they said software update. Code went away. 2500 miles code reappears and took it in again where they adjusted "software" again. Following week, code appeared again and they have had my truck since. going on 5 weeks Replaced, DEF filters, sensors and now they are working on catalytic converter. GM engineer is using my truck as R&D at this point and getting a bit frustrated but at least they are making my payments and have given me a loaner. Was getting 30+ plus mpg on freeway unloaded, 25 when loaded up, gear and passengers Ill keep updating but hoping this is the last addition before my truck comes back,