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:
Volvo Sensus
Center console control panel
1 - Volvo Navigation System (VNS)* – NAV: see the separate VNS manual for operating
instructions.
2 - Infotainment (RADIO, MEDIA, TEL*): see the infotainment system ...
Marker lines
The PAC system's lines
1 Marker line for a 1-foot (30-centimeter)
zone behind the vehicle
2 Marker line for the clear back-up zone
3 "Wheel tracks"
The solid line (1) indicates a zon ...
Fault tracing and actions
If the message Radar blocked See manual is displayed, this means that the radar
signals from the sensor have been obstructed and that a vehicle ahead cannot be
detected.
This, in turn, means that ...
