This document supersedes SAE J1979 May 2007, and is technically equivalent to ISO 15031-5 2010, with the addition of new capabilities required by revised regulations from the California Air Resources Board and revised regulations from the European Commission. This document is intended to satisfy the data reporting requirements of On-Board Diagnostic (OBD) regulations in the United States and Europe, and any other region that may adopt similar requirements in the future. This document specifies:

1. a message formats for request and response messages,
2. b timing requirements between request messages from external test equipment and response messages from vehicles, and between those messages and subsequent request messages,
3. c behavior of both the vehicle and external test equipment if data is not available,
4. d a set of diagnostic services, with corresponding content of request and response messages, to satisfy OBD regulations,

This document includes capabilities required to satisfy OBD requirements for multiple regions, model years, engine types, and vehicle types. Those regulations are not yet final for some regions, and are expected to change in the future. This document makes no attempt to interpret the regulations and does not include applicability of the included diagnostic services and data parameters for various vehicle applications. The user of this document is responsible to verify the applicability of each section of this document for a specific vehicle, engine, model year and region. SAE J1979/ISO 15031-5 specifies diagnostic services and functionally addressed request/response messages required to be supported by motor vehicles and external test equipment for diagnostic purposes which pertain to motor vehicle emission-related data. Any external test equipment meeting the requirements of SAE J1978 is intended to be able to use these messages to retrieve emissions-related information from the vehicle. Each section of this part of SAE J1979/ISO 15031-5 which specifies additional detail to existing sections of ISO 9141-2, ISO 14230-4, SAE J1850, and ISO 15765-4 supersede those specifications. This part of SAE J1979/ISO 15031-5 references the SAE J1979-DA (Digital Annex), which includes all definitions of PIDs, OBDMIDs, TIDs and INFOTYPES.