SAE J1979/ISO 15031-5 set includes the communication between the vehicle’s OBD systems and test equipment implemented across vehicles within the scope of the legislated emissions-related OBD.
To achieve this, it is based on the Open Systems Interconnection (OSI) Basic Reference Model in accordance with ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication systems into seven layers. When mapped on this model, the services specified are broken into:
— Diagnostic services (layer 7), specified in:
— ISO 15031-5/SAE J1979 (emissions-related OBD),
— ISO 27145-3 (WWH-OBD),
— Presentation layer (layer 6), specified in:
— ISO 15031-2, SAE J1930-DA,
— ISO 15031-5, SAE J1979-DA,
— ISO 15031-6, SAE J2012-DA,
— ISO 27145-2, SAE J2012-DA,
— Session layer services (layer 5), specified in:
— ISO 14229-2 supports ISO 15765-4 DoCAN and ISO 14230-4 DoK-Line protocols,
— ISO 14229-2 is not applicable to the SAE J1850 and ISO 9141-2 protocols,
— Transport layer services (layer 4), specified in:
— DoCAN: ISO 15765-2 Transport protocol and network layer services,
— SAE J1850: ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
— ISO 9141-2: ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
— DoK-Line: ISO 14230-4, ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
— Network layer services (layer 3), specified in:
— DoCAN: ISO 15765-2 Transport protocol and network layer services,
— SAE J1850: ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
— ISO 9141-2: ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
— DoK-Line: ISO 14230-4, ISO 15031-5/SAE J1979 Emissions-related diagnostic services,
Rationale:
Changes have been made to keep pace Californian Air Resources Board legislation: Title 13, CCR Section 1968.2. Malfunction and Diagnostic System Requirements--2004 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines and Section 1971.1. On-Board Diagnostic System Requirements--2010 and Subsequent Model-Year Heavy-Duty Engines. The majority of the changes are captured in the J1979DA document.
Included in: On-Board Diagnostics for Light and Medium Duty Vehicles Subscription Learn More
Related Topics:
Spark ignition engines
Diesel / compression ignition engines
On-board diagnostics (OBD)
Emissions control
Electronic control units
Electronic control systems
Control systems
Test equipment and instrumentation
Also known as: SAE J 1979
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