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:
Symbols in the instrument panel
WARNING
If and
come on at the same time and the brake
level is below the MIN mark in the reservoir or if a brake system-related message
is shown in the information display: DO NOT DRIVE ...
Keylock
When you switch off the ignition, the gear
selector must be in the P (Park) position before
the key can be removed from the ignition
switch. ...
Troubleshooting
If Windscreen Sensors blocked appears in the information display, this indicates
that the City Safety™ laser sensor is obstructed in some way and cannot detect vehicles
ahead of you, which means t ...
