It might be $0281 or $0280 which means no connection is being made to the vehicle. If you have already loaded the tune files to the AutoCal, you will now plug the AutoCal into your vehicle and turn the ignition to the Run position with the engine off. Hit Next on the AutoCal until you see the Prog function with the tune file name ModTune. Then you will hit OK. You should see on the screen that it is flashing in and then it will say Completed or something along those lines and to Turn off the ignition now.
If you hit OK when you find the Prog function with the file name and it gives you an $0281 or $0280 error, please ensure the engine isn't running, the cigarette lighter fuse is not blown, and if you have any aftermarket electronics, have the radio fuse pulled as that can block communication with PCM.