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:
Automatic relocking
If the doors are unlocked, the locks will automatically reengage (re-lock) and
the alarm will rearm after 2 minutes unless a door or the trunk has been opened. ...
Erasing warning messages
When a low tire pressure warning message has
been displayed, and the tire pressure warning
light has come on:
1. Use a tire pressure gauge to check the
inflation pressure of all four tires.
2. ...
Station search
1. Choose radio mode AM/FM1/FM2 using
the SELECTOR control (3) or the AM/FM
button (1).
2. Press briefly on to search
for the next strong station. The radio will
search for the next audible st ...
