The Tech2 is propriety GM, and such is capable of communicating with all of the car’s ECU-driven systems – transmission, central locking, ABS, etc.
Generic ODB-II readers will typically only read the engine ECU. This is what made the ‘cheapo’ Tech2 so interesting – it seems to be able to communicate with all of the car’s propriety systems, pretty much like the real Tech2, even if it did not have all of the functionality of the real thing.
But the results were disappointing so far, as even though the various modules and ECU’s are listed in the software main menu, most of them failed to work and did not communicate with the car. The assumption was that the hardware can do the job, and the faults are with software (buggy, and in Hungarian...) – but until we see a fully working example of software and hardware, it is not possible to say for sure.
I still think that as an engine code reader the 'cheapo' Tech2 is worth the £45 buying price. And it does seem to be able to reset codes, something which again most generic code readers don’t do (not the cheap ones anyway).