If I understand what you're asking....you have to have the specific tool to reset the light.

As for the emissions testing...I am a student at an automotive tech school, and an instructor told our class that many states are going to the OBDII emissions test. Essentially the theory goes that if the computer runs the systems diagnostics and the system passes all the tests the car is within the emissions guidelines. It is much faster to do emissions testing this way. Using the OBDII port you can pass a car in several minutes while the dyno method would take several minutes just to get the car ready for testing.

BTW you could talk to your representatives and get them to allow for all OBDII cars to be tested this way.

Neal