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:
Taking out the spare wheel
1. Open the floor hatch.
2. Undo the retaining bolt.
3. Lift out the foam block.
4. Lift out the spare wheel.
The other two blocks can remain in the spare
wheel well.
After use
The foam block ...
Radio text
Some stations transmit information on program
content, artists, etc. This information can
be shown on the display.
Activate/deactivate in FM mode under Show
radio text. ...
Loss of a remote key
If either of the remote keys is lost, the other
should be taken with the car to a Volvo retailer.
As an anti-theft measure, the code of the lost
remote key must be erased from the system.
NOTE
...
