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:
Checking settings
The current Collision Warning settings can be
checked by pressing MY CAR on the center
console control panel and going to Settings
Car settings
Driver support systems
Collision Warnin ...
Start
Ignition switch with remote key inserted ( see page 86 for more
information on ignition modes)
WARNING
Before starting the engine:
Fasten the seat belt.
Check that the seat, steering ...
Changing wheels with TPMS
Please note the following when changing or replacing the factory installed TPMS
wheels/ tires on the vehicle:
Only the factory-mounted wheels are equipped with TPMS sensors in the valves.
If t ...
