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:
Location of the keyless drive antennas
The keyless drive system has a number of antennas located at various points in
the vehicle.
1 - On the inside center of the rear bumper
2 - Left rear door handle
3 - Center of the parcel shelf, ...
Quality and equipment
In the Volvo XC90 considerable importance has been attached to providing a
comprehensive standard specification to reflect the upmarket ambience of the car
itself.
Luxurious touches such as the ...
Minimum octane
Typical pump octane label
Volvo recommends premium fuel for best performance,
but using 87 octane or above will
not affect engine reliability.
Volvo engines are designed to achieve rated
hor ...
