SAE International

(R) E/E Diagnostic Test Modes
 N J1979

Annotation

Introduction

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:

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ISO 15031-5/SAE J1979 (emissions-related OBD),

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ISO 27145-3 (WWH-OBD),

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Presentation layer (layer 6), specified in:

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ISO 15031-2, SAE J1930-DA,

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ISO 15031-5, SAE J1979-DA,

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ISO 15031-6, SAE J2012-DA,

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ISO 27145-2, SAE J2012-DA,

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Session layer services (layer 5), specified in:

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