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:
Changing the set speed
After a speed has been set, it can be increased
or decreased by using the or
buttons.
Each time one of these buttons is pressed, the
vehicle's speed changes by 5 mph
(approximately 8 km/h). ...
Front park assist
The distance monitored in front of the vehicle is approximately 2.5 ft (0.8 m).
The audible signal comes from the audio system's front speakers.
It may not be possible to combine auxiliary he ...
Blower function to reduce battery drain
The climate system's blower functions normally
while the engine is running.
However, when the engine is switched off
(even if the ignition is switched to positions I or
II), the blower control w ...
