How do states use OBD II for emission inspections?

Many states connect a computer directly to a vehicle's OBD II system. The inspector can then read "faults." In some states, this type of inspection has replaced the tailpipe emission test.
See also:
Power door mirrors
Door mirror controls ...
Volvo's recommendations
Why does Volvo believe that no child should sit
in the front seat of a car? It's quite simple really.
A front airbag is a very powerful device
designed, by law, to help protect an adult.
Becau ...
Limitations
Main channel vs. sub-channels (FM only): The main channel is the only channel
that can receive in hybrid mode (both digital and analogue). If a frequency
has subchannels, they are broadcast i ...
