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:
Steering wheel keypad
The keypad varies according to the vehicle's equipment
1 - Turn the thumb wheel to go up/down among menu selections. Press the thumb
wheel to make a selection or store a function in the syste ...
Pairing and connecting an external device
Before an external device can be connected, it must be paired to the infotainment
system. The procedure for connecting an external device varies, depending whether
or not the device has previously ...
Common functions: Remote key/ Personal Car Communicator (PCC)*
Personal Car Communicator (PCC)*
Lock
Unlock
Approach lighting
Trunk unlock/open
Panic alarm ...
