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 Overview
Volvo's small wagon, the V50, comes in 2.4i and T5 trim levels, the latter
offered in all- as well as front-wheel drive. A few years past a full redesign,
the V50 and its S40 sedan sister have bee ...
Driving dynamics: engine
The second-generation, 2.4-litre, five-cylinder, diesel D5 is a cleaner and
more advanced version of the engine fitted to the outgoing XC70. It gives superb
performance (130mph) allied to fuel eco ...
Standby mode (temporary deactivation)
Press to temporarily deactivate
cruise control
(put it in standby mode). The set speed, for
example 55 mph, is then shown in parentheses.
The previously set speed and time interval are
resum ...
