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:
Instrument overview
Instrument overview
1 Menus and messages, turn signals, high/low beams, trip
computer
2 Cruise control
3 Horn, airbag
4 Main instrument
panel
5 Audio system/Bluetooth
hands-free
cont ...
Location of taillight bulbs
Brake lights (LEDs)
Brake light
Backup light
Turn signals
Rear fog light (driver’s side only)
NOTE
If an error message remains in the display after a faulty bulb has been replace ...
Brake lights
The brake lights come on automatically when
the brakes are applied.
Adaptive brake lights
The adaptive brake lights activate in the event
of sudden braking or if the ABS system is activated.
Th ...
