SAE J1979_202505

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, — Data link layer (layer 2), specified in: — DoCAN: ISO 15765-4, ISO 11898-1, -2, — SAE J1850, — ISO 9141-2, — DoK-Line: ISO 14230-2, — Physical layer (layer 1), specified in: — DoCAN: ISO 15765-4, ISO 11898-1, -2, — SAE J1850, — ISO 9141-2, — DoK-Line: ISO 14230-1, in accordance with Table 1. 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. SAE J1979 has been reaffirmed to comply with the SAE Five-Year Review policy.