标准摘要
[中文适用范围]： 本标准规定了机动车和外部测试设备为诊断目的（特别是与机动车排放相关的数据）必须支持的诊断服务和功能寻址/物理寻址的请求/响应消息格式。适用于满足美国、欧洲及其他地区排放相关 OBD 法规要求的乘用车及轻、中、重型卡车。它定义了用于检索车载诊断（OBD）信息的消息格式、请求与响应之间的时间要求、数据不可用时的行为，以及一套满足 OBD 法规的诊断服务。 [外文原描述]： SAE J1979-2 describes the communication between the vehicle’s OBD systems and test equipment required by OBD regulations. 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:○ ISO 14229-1○ SAE J1979-2 OBDonUDS• Presentation layer (layer 6), specified in:○ SAE J1930, SAE J1930DA○ SAE J1979DA○ SAE J2012, SAE J2012DA○ SAE J1939DA, SAE J1939-73• Session layer services (layer 5), specified in:○ ISO 14229-2• Transport layer services (layer 4), specified in:○ DoCAN: ISO 15765-2 Transport protocol and network layer services○ ISO 15765-4 Requirements for emissions related systems○ 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:○ DoCAN: ISO 15765-2 Transport protocol and network layer services○ ISO 15765-4 Requirements for emissions related systems○ 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:○ DoCAN: ISO 15765-4, ISO 11898-1, ISO 11898-2○ 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:○ DoCAN: ISO 15765-4, ISO 11898-1, ISO 11898-2, in accordance with Table 1○ DoIP: ISO 13400-3 Road vehicles - Diagnostic communication over Internet Protocol (DoIP) - Part 3: Wired vehicle interface based on IEEE 802.3NOTE: SAE J1979-2 provides a STANDARD to satisfy known country-specific OBD regulations. SAE J1979-2 is not considered a final authority for interpretation of the OBD regulations, so users of this document should determine the applicability of capabilities defined in this document for their specific OBD regulatory requirements.
英文名称E/E Diagnostic Test Modes: OBDonUDS