Actron CP9175 OBD II AutoScanner - Manual (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.