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:
Vehicle loading
Properly loading your vehicle will provide maximum
return of vehicle design performance.
Before loading your vehicle, familiarize yourself
with the following terms for determining your
vehicle's ...
MEDIA menus
Main CD Audio menu Disc menu
Random Scan Audio settings
Main CD/DVD Data menu Disc menu
Play/Pause Stop Random Repeat folder Change subtitles Change audio
track Scan Audio sett ...
Faults in the system
If the information symbol illuminates and Park assist syst Service required is
shown on the information display, this indicates that the system is not functioning
properly and has been disengaged. ...
