The DAD ois is the new system for cars 2000 and newer it plugs directly into the obd port and looks at the vehicles computer data
What about 1996-2000? We have never run OBD-II compliant cars on dyno for emissions, that’s the whole point of OBD-II.
I’m in Washington State, what are these points people are referring to? What’s the difference to the shop if the car passes or fails? Seems like that’s the customer’s problem.