gm tech 3...never heard of such a thing. must be aftermarket. gm's laptop based system is gds2.

 

Thanks for saving me from a stupid buy of scantool.
I called back and specificly asked if it works on my US Chevy and got an half maybe but......maybe not.
Its for European GM as SAAB and Opel/Vauxhall and a China clone of GM´s electronic and needs an USB dongle/key to work so i skipp this one