All diesel applications except 11+ Duramax:
1. Make sure the GT programming is installed
2. Press the top right button to increase the power level and the bottom right button to decrease power level.
Gas applications and 2011+ Duramax diesel:
1. Go to install download
2. Select Modify settings or modify tuning when prompted.
3. Follow the onscreen downloading instructions
Our Technical Support team is here for you.Contact Support