See also:

What is an Onboard Diagnostic System (OBD II)?
OBD II is part of your vehicle's computerized engine management system. It stores diagnostic information about your vehicle's emission controls. It can light the Check Engine light (MIL) if it ...

Limitations
In certain situations, DAC may provide warnings even if the driver’s driving pattern has not become erratic. • if the driver is testing the LDW function • in strong crosswinds • on grooved road ...

The Federal Clean Air Act – U.S.
The Federal Clean Air Act requires vehicle manufacturers to furnish written instructions to the ultimate purchaser to assure the proper servicing and function of the components that control emissi ...