This video shows the difference between a "Generic" OBDII scan tool and a "Factory Dealer Level" scan tool.
In almost all scenarios a "Generic" scan tool will not help diagnose anything, it will just display a fault code and leave you to fend for yourself.
ONLY the dealer scan tool will provide you with guided tests in MOST cases. The GM TECHII scan tool is great except when you get a fault code you still need access to the GM dealer portal to find the guided test steps. I have worked in the Mercedes-Benz dealers for just about 15 years and that included Porsche, Audi, VW and also I dabbled with GM on a dealer level but I have always been a GM fan at heart.
I can help with almost any make and model, I say that because in some cases the aftermarket information is not trustworthy and missing in most other cases. For instance I use sources like ALLDATA and IDENTIFIX for wiring and code lookup but for some reason European and Asian cars are lacking on the back end.
But again the basis for this video is to show that if you say, have a transmission error, the check engine light is on, and there are no codes In the engine module except for maybe a P0720 or similar, you still need a better scan tool to access the transmission module for the exact code that is there. So it is always important to use the right tool for the job. Now if you are a technician you might be saying, "Lou, I can fix anything with a generic scan tool" I would agree but i'm sure your experience in the automotive field is more than 5 years. Where most of the people I assist have little to know automotive background or experience.
So I hope this video helps explain a little bit more about why you need a certain scan tool.

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