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:
Disc eject
For reasons of traffic safety, an ejected disc
must be removed within 12 seconds or it will
be automatically drawn back into the slot. ...
Symbols in the main instrument panel
Warning symbols
Indicator symbols
Other information symbols
Information symbols in the center console display
Information symbols in the ceiling console
...
ISOFIX/LATCH lower anchors
Using the ISOFIX/LATCH lower child
seat anchors
ISOFIX/LATCH lower child restraint anchors
Lower anchors for ISOFIX/LATCH-equipped
child seats are located in the second row, outboard
seats, hid ...
