What's EOBD

    The American Environment Protection Agency and also the European parliament have

set targets for lowering the amounts of pollution created by passenger and commercial

automobiles. To be able to make sure that these targets could be met, producers are needed

to construct new automobiles which meet progressively stiff pollutants standards. The

producers must further maintain these emission standards for that helpful existence of

the automobile. To be able to meet and keep these standards the automobiles are fitted with

On-Board Diagnostic systems which monitor the integrity and effectiveness of

emission related components.

As automobiles are becoming a lot more complex, most of the systems suited to

options are being controlled by electronic control modules. Most automobiles are in possession of

multiple control modules (e.g. Engine, Transmission, Body, Suspension, etc.) situated

at different locations around the vehicle. The On-Board Diagnostic systems are integrated

in to the vehicle control modules.

Because of so many different vehicle and component producers, a typical interface

was needed to talk with these control modules. In 1988, the SAE (Society

of Automotive Engineers) produced a typical that defined a typical diagnostic

socket (J1962) and some diagnostic test signals.

Using the diagnostic socket and diagnostic signals agreed, another standard was

created that defined a universal inspection and diagnosis method to make sure that a

vehicle is carrying out to Original Equipment Manufacturer (OEM) specifications. This

standard is called EOBD (European On-Board Diagnostics).

The essential requirement of an EOBD product is that in case of an pollutants

related component fault, a DTC (Diagnostic Trouble Code) is going to be saved within the

memory from the control module responsible for your component, along with a Malfunction

Indicator Light (MIL) will illuminate around the vehicle's instrument pack to alert the motive force.

The DTC may then be retrieved using diagnostic equipment to look for the type and

status from the fault.