OBD Standards documents

SAE standards documents on OBD-II

• J1962 – Defines the physical connector used for the OBD-II interface.
• J1850 – Defines a serial data protocol. There are 2 variants- 10.4 kbit/s (single wire, VPW) and 41.6 kbit/s (2 wire, PWM). Mainly used by US manufacturers, also known as PCI (Chrysler, 10.4K), Class 2 (GM, 10.4K), and SCP (Ford, 41.6K)
• J1978 – Defines minimal operating standards for OBD-II scan tools
• J1979 – Defines standards for diagnostic test modes
• J2012 – Defines standards trouble codes and definitions.
• J2178-1 – Defines standards for network message header formats and physical address assignments
• J2178-2 – Gives data parameter definitions
• J2178-3 – Defines standards for network message frame IDs for single byte headers
• J2178-4 – Defines standards for network messages with three byte headers*
• J2284-3 – Defines 500K CAN Physical and Data Link Layer
• J2411 – Describes the GMLAN (Single-Wire CAN) protocol, used in newer GM vehicles. Often accessible on the OBD connector as PIN 1 on newer GM vehicles.

SAE standards documents on HD (Heavy Duty) OBD

• J1939 – Defines a data protocol for heavy duty commercial vehicles

ISO standards

• ISO 9141: Road vehicles — Diagnostic systems. International Organization for Standardization, 1989.
  • Part 1: Requirements for interchange of digital information
  • Part 2: CARB requirements for interchange of digital information
  • Part 3: Verification of the communication between vehicle and OBD II scan tool
• ISO 11898: Road vehicles — Controller area network (CAN). International Organization for Standardization, 2003.
  • Part 1: Data link layer and physical signalling
  • Part 2: High-speed medium access unit
  • Part 3: Low-speed, fault-tolerant, medium-dependent interface
  • Part 4: Time-triggered communication
• ISO 14230: Road vehicles — Diagnostic systems — Keyword Protocol 2000, International Organization for Standardization, 1999.
  • Part 1: Physical layer
  • Part 2: Data link layer
  • Part 3: Application layer
  • Part 4: Requirements for emission-related systems
• ISO 15031: Communication between vehicle and external equipment for emissions-related diagnostics, International Organization for Standardization, 2010.
  • Part 1: General information and use case definition
  • Part 2: Guidance on terms, definitions, abbreviations and acronyms
  • Part 3: Diagnostic connector and related electrical circuits, specification and use
  • Part 4: External test equipment
  • Part 5: Emissions-related diagnostic services
  • Part 6: Diagnostic trouble code definitions
  • Part 7: Data link security
• ISO 15765: Road vehicles — Diagnostics on Controller Area Networks (CAN). International Organization for Standardization, 2004.
  • Part 1: General information
  • Part 2: Network layer services ISO 15765-2
  • Part 3: Implementation of unified diagnostic services (UDS on CAN)
  • Part 4: Requirements for emissions-related systems