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:
Interior rearview mirror
Auto-dim function
An integrated sensor reacts to headlights from
following traffic and automatically reduces
glare in the mirror. ...
Tire sealing system–overview
Speed limit sticker
On/Off switch
Electrical wire
Bottle holder (orange cover)
Protective hose cover
Air release knob
Hose
Bottle with sealing compound
Air pressure gauge
...
Power seat
Operation
Driver's seat: The seat can be adjusted if the
ignition key is in position I, II or if the engine is
running. It can also be adjusted as follows with
the ignition off:
• Within severa ...
