VDO CONTISYS OBD - V3.0, Instruction Manual

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EOBD Application
11
EOBD Application
What is EOBD?
The American Environmental Protection Agency and the European government have
set targets for reducing the levels of pollution produced by passenger and commercial
vehicles. In order to ensure that these targets can be met, manufacturers are required
to build new vehicles which meet increasingly stiff emissions standards. The
manufacturers must further maintain these emission standards for the useful life of the
vehicle. In order to meet and maintain these standards the vehicles are fitted with On-
Board Diagnostic systems which monitor the integrity and effectiveness of all emission
related components.
As vehicles are becoming more and more complex, many of the systems fitted to
them are being controlled by electronic control modules. Most vehicles now have
multiple control modules (e.g. Engine, Transmission, Body, Suspension, etc.) located
at different locations on the vehicle. The On-Board Diagnostic systems are integrated
into the vehicle control modules.
With so many different vehicle and component manufacturers, a common interface
was required to communicate with these control modules. In 1988, the SAE (Society
of Automotive Engineers) created a standard that defined a standard diagnostic
socket (J1962) and a set of diagnostic test signals.
With the diagnostic socket and diagnostic signals agreed, another standard was
produced that defined a universal inspection and diagnosis method to ensure that a
vehicle is performing to Original Equipment Manufacturer (OEM) specifications. This
standard is known as EOBD (European On-Board Diagnostics).
The fundamental requirement for an EOBD system is that in the event of an emissions
related component fault, a DTC (Diagnostic Trouble Code) will be stored in the
memory of the control module responsible for that component, and a Malfunction
Indicator (MI) lamp will illuminate on the vehicle's instrument pack to alert the driver.
The DTC can then be retrieved using diagnostic equipment to determine the type and
status of the fault.