Did you make sure that the key was in the right position? I know that in my car if I try to scan it/whatever with the tool it fails out when the key is in but the off position, but works fine when I turn the key to AC or the next step up (but not to on or the one before the ignition).
Might wanna try that, because I know that I was going crazy myself for a while trying to figure out why my new shiny scanner wasn't working, till I realized to try and turn the key more. Different cars have different settings on the ignition cylinder where the computer makes an outbound connection, so what might have worked on your impala doesn't mean it will work on the camaro.
2006 Pontiac GTO | Intake | Predator Tuned | Spintech Exhaust