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:
Driving dynamics: engines
The Volvo S80 is the best handling, most agile, and best-performing big Volvo
saloon ever. New versions of Volvo's renowned five-cylinder common-rail diesel
engines produce excellent fuel economy ...
General functions
1 RADIO button for selecting the AM, FM1,
FM2, Sirius1* or Sirius2* wavebands.
2 Number key buttons (0-9).
3 Navigate among the menu alternatives in
the display by turning TUNE.
4 Confirm you ...
Automatic transmission
Shiftgate positions
Depress the button on the front of the gear
selector knob to move the gear selector
between the R, N, D, and P positions.
The gear selector can be moved freely between
th ...
