SAE J 1979-2:2021-04-22
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SAE J 1979-2:2021-04-22

E/E Diagnostic Test Modes: OBDonUDS

Summary

SAE J1979-2 describes the communication between the vehicle's OBD systems and test equipment required by OBD regulations. On-Board Diagnostic (OBD) regulations require passenger cars and light-, medium-, and heavy-duty trucks to support a minimum set of diagnostic information to external (off-board) “generic” test equipment.
To achieve this, SAE J1979-2 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:
    1. ?
      ISO 14229-1
    2. ?
      SAE J1979-2 OBDonUDS
  • Presentation layer (layer 6), specified in:
    1. ?
      SAE J1930, SAE J1930DA
    2. ?
      SAE J1979DA
    3. ?
      SAE J2012, SAE J2012DA
    4. ?
      SAE J1939DA, SAE J1939-73
  • Session layer services (layer 5), specified in:
    1. ?
      ISO 14229-2
  • Transport layer services (layer 4), specified in:
    1. ?
      DoCAN: ISO 15765-2 Transport protocol and network layer services
    2. ?
      ISO 15765-4
    3. ?
      DoIP: ISO 13400-2 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 2:Transport protocol and network layer services
  • Network layer services (layer 3), specified in:
    1. ?
      DoCAN: ISO 15765-2 Transport protocol and network layer services
    2. ?
      ISO 15765-4 Requirements for emissions related systems
    3. ?
      DoIP: ISO 13400-2 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 2:Transport protocol and network layer services
  • Data link layer (layer 2), specified in:
    1. ?
      DoCAN: ISO 15765-4, ISO 11898-1, -2
    2. ?
      DoIP: ISO 13400-3 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 3: Wired vehicle interface based on IEEE 802.3
  • Physical layer (layer 1), specified in:
    1. ?
      DoCAN: ISO 15765-4, ISO 11898-1, -2, in accordance with Table 1
    2. ?
      DoIP: ISO 13400-3 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 3: Wired vehicle interface based on IEEE 802.3

Technical characteristics

Publisher SAE International
Publication Date 04/22/2021
Page Count 96
EAN ---
ISBN ---
Weight (in grams) ---
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