2016 sierra denali 5.3l 2wd

[Juanm3700]

Hi is there a way to tune the car even though it has already been tuned by someone else

[06MonteSS]

you'd want to have the factory stock GM programming on the vehicle before using a diablo tool on it..

have the other person put the factory stock GM tune back on the truck's ECM/TCM modules.. . or have your dealer flash them to the latest GM factory tunes...