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:
Refueling
The fuel tank is designed to accommodate
possible expansion of the fuel in hot weather.
See page 284 for fuel tank volume. Be aware
that the "usable" tank capacity will be somewhat
les ...
Deactivation
Move the gear selector from R to another position. There is a slight delay in
the PAC system, which means that the view from behind the vehicle will remain on
the screen for approximately 15 secon ...
Steering wheel adjustment
Both the height and the reach of the steering
wheel can be adjusted to a comfortable position
for the driver. Pull down the lever on the
left of the steering column. Adjust the steering
wheel to ...
