[Diesel_Dave]

What's your concern? Is it passing a certain inspection that's required by the locality that your vehicle is registered in?

Emissions regulations are pretty complicated in how they're structured. There are certain standards that manufacturers have to meet in order to sell a engine/vehicle in a certain region (usually by country). However, there are different standards for after the vehicle has been sold. Some locaties require no inspection whatsoever, so technically after it's sold off the lot, nothing matters. Some locatities require that, when inpected the "check engine" light is off (supposedly indicating that everything is in proper working order such that the emissions should theoretically be okay). Other localities require an inspection where the vehicle is actually run through some standard test cycle and the emissions are measured.

Your specific requirements will depend on what locality you're in. I know where I live in Indiana currently there are no inspections at all. I used to live in PA, where all counties had a general safety inspection, but only certain counties required an emissions check.