E/E Diagnostic Test Modes: OBDonUDS
Authors:   Vehicle E E System Diagnostic Standards Committee
Published: April 2021

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<div class="htmlview paragraph">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.</div>
<div class="htmlview paragraph">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:</div>
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<div class="htmlview paragraph">Diagnostic services (layer 7), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">ISO 14229-1</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">SAE J1979-2 OBDonUDS</div></li></ol></div></li>
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<div class="htmlview paragraph">Presentation layer (layer 6), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">SAE J1930, SAE J1930DA</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">SAE J1979DA</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">SAE J2012, SAE J2012DA</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">SAE J1939DA, SAE J1939-73</div></li></ol></div></li>
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<div class="htmlview paragraph">Session layer services (layer 5), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">ISO 14229-2</div></li></ol></div></li>
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<div class="htmlview paragraph">Transport layer services (layer 4), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoCAN: ISO 15765-2 Transport protocol and network layer services</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">ISO 15765-4</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoIP: ISO 13400-2 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 2:Transport protocol and network layer services</div></li></ol></div></li>
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<div class="htmlview paragraph">Network layer services (layer 3), specified in:
<ol class="list nostyle">
<li class="list-item">
<span class="li-label">○</span>
<div class="htmlview paragraph">DoCAN: ISO 15765-2 Transport protocol and network layer services</div></li>
<li class="list-item">
<span class="li-label">○</span>
<div class="htmlview paragraph">ISO 15765-4 Requirements for emissions related systems</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoIP: ISO 13400-2 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 2:Transport protocol and network layer services</div></li></ol></div></li>
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<div class="htmlview paragraph">Data link layer (layer 2), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoCAN: ISO 15765-4, ISO 11898-1, -2</div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoIP: ISO 13400-3 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 3: Wired vehicle interface based on IEEE 802.3</div></li></ol></div></li>
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<div class="htmlview paragraph">Physical layer (layer 1), specified in:
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoCAN: ISO 15765-4, ISO 11898-1, -2, in accordance with <span class="xref">Table 1</span></div></li>
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<span class="li-label">○</span>
<div class="htmlview paragraph">DoIP: ISO 13400-3 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 3: Wired vehicle interface based on IEEE 802.3</div></li></ol></div></li></ul>

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