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OBD-II HISTORY
What is OBD-II?
OnBoard Diagnostics Version 2 (OBD-II) is in all passenger
vehicles manufactured for sale in the U.S. since 1996. It has three
main purposes, it: 1) alerts the vehicle operator if the vehicle’s
emissions output rises in response to a system failure; 2) performs
real-time analysis of the engine’s performance to help
manufacturers achieve regulated vehicle fuel economy; and, 3)
standardizes the electrical and communications protocols for the
automotive industry. OBD-II has allowed vehicle manufacturers to
stay within the Environmental Protection Agency’s (EPA)
emissions guidelines, and made it easier to diagnose problems in a
wide variety of vehicles using only one tool. OBD is more or less a
sophisticated data-acquisition system for vehicle emissions and
performance.
What is the History Behind OBD-II?
In 1955 the government took notice of the detrimental effects
that car emissions were having on the atmosphere. Early laws were
passed that gave vehicle manufacturers strict guidelines to follow
with regard to vehicle emissions. These laws were generally
ignored until 1988 when the Society of Automotive Engineers
(SAE) proposed several standards, and the Air Resources Board
(ARB) mandated them on all 1988 and later vehicles. These
mandates were, in effect, OBD-I.
The original OBD was a simple system that monitored the
oxygen sensors, exhaust gas recirculation (EGR) system, fuel
delivery system, and the engine control module (ECM) for
excessive emissions. Unfortunately, different car manufacturers
complied with the ARB’s mandates in different ways. In fact,
compliance was so varied that a new problem developed.
The problem was that manufacturers had equipped their
vehicles with OBD systems that weren’t standardized.
Consequently, each manufacturer had it’s own set of fault codes and
it’s own tools to interpret the codes. Independent repair facilities
across the country were struggling to diagnose vehicles with such a