Chapter 5
Hanatech Co., Ltd..
Chapter 5 - 1
Generic OBD2
I. Literal definition of OBD and OBD2-------
OBD is an abbreviation for On Board Diagnostics. OBD-1 is in reference to
Title 13 California Code 1968 titled "Malfunction and Diagnostic System for
1988 and Subsequent Model Year Passenger Cars, Light-Duty Trucks, and
Medium-Duty Vehicles with Three-Way Catalyst Systems and Feedback
Control." filed on 11-15-85. This required cars sold in California to have an
on-board computer processor for on-board self-diagnostics of computer
sensed emission related components, fuel metering device and EGR
(exhaust gas recalculation system). A partial or total malfunction that
exceeded exhaust emission standard would illuminate a MIL (malfunction
indicator light) and provide on-board identification of the malfunction
location. To provide malfunction location information, codes are stored in on-
board computer memory. To read codes manufactures use methods, such
as flashing MIL light or various serial data protocols.
OBD-2 is in reference to Title 13 California Code 1968.1 titled "Malfunction
and Diagnostic System Requirements-1994 and Subsequent Model-Year
Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and
Engines. Filed on 8-27-90 to Air Resouce Board (ARB)
This requires a standard electrical connector, open source standardized
diagnostic trouble codes (DTC), data, and communication protocol with more
specific self-diagnostic on-board monitoring of emission malfunctions.
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