OBD-II Diagnostics.

On-board Diagnostic (OBD) is a vehicle's computerized diagnostic and reporting capability.  OBD systems give the vehicle owner or repair technician access to the status of the various vehicle sub-systems.  Modern OBD implementations use a standardized digital communications port to provide real-time data in addition to a standardized series of diagnostic trouble codes (DTC), which then allow a person to rapidly identify and remedy malfunctions within the vehicle.

Why On-Board Diagnostic (OBD)

Clean Air Goal

In 1970, Congress passed the first major Clean Air Act, requiring a 90 percent reduction in emissions from new automobiles by 1975. President Richard Nixon established Environmental Protection Agency (EPA), and the new agency was given broad responsibility for regulating motor vehicle pollution.

Established in 1991

The California Air Resource Board requires that all new vehicles sold in California in 1991 and newer vehicles have some basic on-board diagnostics (OBD) capability. These requirements are generally referred to as "OBD-I", though this name is not applied until the introduction of "OBD-II".

Development of OBD-II Specifications

1988

The Society of Automotive Engineers (SAE) recommends a standardized diagnostic connector and set of diagnostic test signals.

1994 

California mandates starting in model year 1996, OBD-II specification be adopted for all cars sold in California.

1996

The OBD-II specification is made mandatory for all cars sold in the United States.

We're Here for You and The Environment

In the United States, many states now use OBD-II testing instead of tailpipe testing in OBD-II compliant vehicles (1996 and newer).  Since OBD-II stores trouble codes for emissions equipment, the testing computer can query the vehicle's onboard computer and verify there are no emission related trouble codes and that the vehicle is in compliance with emission standards for the model year it was manufactured.