USER MANUAL
For MULTISCAN P2
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
communication protocols including 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
opened to public, so that all the scanners 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 emission related parts 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.
