A Closer Look At OBD II diagnostic by aihaozhe2


									On-Board diagnostics is an automotive term which is a term that refers to a self
diagnostic and reporting ability of a vehicle. It gives information of health conditions
of any kind of vehicles to a man who is an owner of car or a mechanic. The OBD
diagnostic information's are available from early of 1980s on the on-board computers.
The early OBD just illuminate a malfunction indicator light only. But if problems
occur, it could not give any important information about the problem as well as the
solving procedure of these problems. On the other hand modern OBD can transmit
diagnostic trouble codes with very fast digital communication port which can identify
false easily and remedy malfunctions in the vehicle. There are several types of OBD
diagnostic are there. Such as OBD 1, OBD 1.5, OBD 2, EOBD, EOBD 2,
HDOBD,chilton auto repair manual etc. Volkswagen introduces the first OBD system.
It upgrades day by day and now heavy duty OBD has introduced to detect the
problems in the vehicles.

In 1987s OBD II has diagnostic has introduces which is more advanced than OBD I in
both capability as well as standardization with the help of Audi Repair manuals. The
type of OBD II diagnostic connector and its pinout, messaging format and electrical
signal protocol is the main specifications of OBD II diagnostic system. As a result of
these specifications it provides an extensible list of DTC. The location of OBD II is
somewhat different from OBD I. OBD II diagnostic lies within two feet from the
staring wheel where as OBD I sometimes lie under the hood of the car. OBD II
diagnostic connector has 16 pins and SAE J1962 defines that pins as:
First pin is manufacturer discretion, second is bus positive line of SAE J1850 PWM
as well as SAE -1850 VPM. Third is for ford DCL positive, forth is chassis ground,
fifth is for signal ground. Tenth is for bus negative line of SAE J1850 PWM only,
eleventh is ford DCL negative, sixteenth is for battery voltage and so on.
When a troubleshooting problem occur inside a vehicle the OBD II creates necessary
data from the engine control unit to the output monitor. OBD II diagnostic is more
advanced system that provides an important role in mechanic field as well as for a
person who has a car. It also provides information to remove all faults and make the
vehicle free and smooth like before.

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