Most TechII diagnostic scanners are not owned by technicians. Most are owned by the GM dealer. Also, reprogramming needs to be done at the dealer when using a TechII. GM software is uploaded into the TechII, then it is downloaded into the vehicle. VIN and software compatibility needs to be verified before the program will download into the vehicle.

You might be better off with a correctly installed aftermarket remote start.

Just some things to think about.