Which diagnostic car scanner does car max use to diagnose its cars?

The auto service technicians probably have to buy their own OBD scanners, so it would be whatever they decide to buy in that instance. The Snap-On Solus Pro is probably pretty common. If you want to buy one, it's about $3900. For $150 - $400, you can buy a lower end model at various auto parts suppliers such as O'Reilly, Auto Zone, Advanced Auto Parts, etc.