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.
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Exterior
Thanks to its redesign, the S60 is not the boxy Volvo from days of old. Sure,
it's a midsize sedan produced by the brand that built its name on safety, but
the S60's exterior looks verge on sexy. ...
Electronic climate control, ECC
Temperature control, driver's side
Heated driver's seat*
Defroster (maximum effect)
Blower
Manual air distribution—floor
Manual air distribution—dashboard air vents
Manual air ...
Center console controls
Center console controls for menu navigation
1 - Press MY CAR to access the My Car menus.
2 - Press OK/MENU to select a highlighted selection or to store a certain function
in the system's me ...
