Actron CP9175 OBD II AutoScanner User Manual download pdf (Page 15)

Getting Started

1-3

Introduction to On-Board Diagnostics

OBD II (On-Board Diagnostics version II) is a system that the

Society of Automotive Engineers (SAE) developed to

standardize automotive electronic diagnosis.

Beginning in 1996, most new vehicles sold in the USA were

OBD II compliant.

✓ Technicians now can use the same tool to test any OBD

II compliant vehicle without special adapters. SAE

established guidelines that provide:

❒ A universal connector, called the Data Link Connector

(DLC), with dedicated pin assignments.

❒ A standard location for the Data Link Connector (DLC),

visible under the dash on driver’s side.

❒ A standard list of diagnostic trouble codes (DTCs) used

by all manufacturers.

❒ A standard list of parameter identification (PID) data

used by all manufacturers.

❒ Ability for vehicle systems to record operating conditions

when fault occurs.

❒ Expanded diagnostic capabilities that records a code

whenever a condition occurs that affects vehicle

emissions.

❒ Ability to clear stored codes from vehicles memory with

Tool.

SAE Publications

SAE has published hundreds of pages of text defining a

standard communication protocol that establishes hardware,

software, and circuit parameters of OBD II systems.

• SAE publishes recommendations, not laws, but the

Environmental Protection Agency (EPA) and California Air

Resources Board (CARB) made many of SAE’s

recommendations legal requirements.

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Actron CP9175 OBD II AutoScanner User Manual Page 15