Bosch CP009 User Manual download pdf (Page 67)

USER MANUAL For DS2020/2021

Chapter 5 - 2

II. More practical notes --------------------------

A. Technical meaning of OBD2

1. Standardization

a For the technicians and scan tool engineers, OBD2 has its technical

meaning as bringing the standardized methods of vehicle diagnosis to

the chaotic aftermarket where dozens of car make use different

diagnostic adapters and communication protocols of their own.

b The 16-pin trapezoid diagnostic adapter and a few of most influential

comm

unication protocols inclu

ding ISO9141-2, KWP2000, and SAE

J1850 VPW and PWM form the standard OBD2 specifications.

c Trouble codes and Data stream variables were also standardized and

open

ed to public, so that all the scann

ers that support aforementioned

standard communication protocols through the 16-pin OBD2 adapter can

always get the same readouts.

2. Purpose of OBD and OBD2

a. OBD and OBD2 are the names of regulation that were legislated in USA

for the emission control.

b. On board diagnostics was implemented to monitor malfunction or failure

of the emissi

on related pa

rts and components to minimize the possibility

of excessive exhaust gas emission by letting the driver know that the car

has a problem and the technician immediately perceive what is the

problem when any trouble is detected in the emission control system.

And OBD2 became effective later to increase the efficiency of OBD by

standardization.

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Bosch CP009 User Manual Page 67