On-Board Diagnostics - Second Generation (Obd 2) - Innova 3100 Owner's Manual

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COMPUTER ENGINE CONTROLS

On-Board Diagnostics - Second Generation (OBD 2)

In addition to performing all the
functions of the OBD 1 System, the
OBD 2 System has been enhanced
with new Diagnostic Programs. These
programs closely
functions of various emissions-related
components and systems (as well as
other systems) and make this information readily
available (with the proper equipment) to the technician for
evaluation.
The California Air Resources Board (CARB) conducted
studies on OBD 1 equipped vehicles. The information that
was gathered from these studies showed the following:
A large number of vehicles had deteriorating or degraded
emissions-related components. These components were causing
an increase in emissions.
Because OBD 1 systems only detect failed components, the
degraded components were not setting codes.
Some emissions problems related to degraded components only
occur when the vehicle is being driven under a load. The emission
checks being conducted at the time were not performed under
simulated driving conditions. As a result, a significant number of
vehicles with degraded components were passing Emissions
Tests.
Codes, code definitions, diagnostic connectors, communication
protocols and emissions terminology were different for each
manufacturer. This caused confusion for the technicians working
on different make and model vehicles.
To address the problems made evident by this study, CARB and the
EPA passed new laws and standardization requirements. These laws
required that vehicle manufacturers to equip their new vehicles with
devices capable of meeting all of the new emissions standards and
regulations. It was also decided that an enhanced on-board
diagnostic system, capable of addressing all of these problems, was
needed. This new system is known as "On-Board Diagnostics
Generation Two (OBD 2)." The primary objective of the OBD 2
system is to comply with the latest regulations and emissions
standards established by CARB and the EPA.
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The OBD 2 System is an
enhancement of the
OBD 1 System.
monitor the
OBD 2