For line lock there are several videos on how to use it do a YouTube search for line lock or launch control. will be the same as the 2015+ GT. for Launch control you have to set the RPMs you want to stage at and put the throttle pedal to the floor in a quick motion, And the motor will not go...
First off did you save the original configuration through Forscan? And this will sound silly but were you in reverse when you tested it? did you check if you get the drive mode unavailable with the steering wheel control? the reverse sensors could be the culprit and may need to be disabled if...