SAE J1979DA-2025 PDF

Full title and description

St SAE J1979DA-2025 — J1979-DA, Digital Annex of E/E Diagnostic Test Modes. This supplement (Digital Annex) accompanies SAE J1979 and maintains a global registry of regulated emissions and propulsion-related data identifiers, providing a machine-readable annex for OBD‑related diagnostic parameters and PIDs used by vehicle ECUs and external test equipment.

Abstract

The J1979-DA Digital Annex complements the SAE J1979 E/E Diagnostic Test Modes standard by cataloguing data identifiers, standardized PIDs, and related metadata used for emissions‑related on‑board diagnostics (OBD). It supports consistent communication between vehicles and external test tools, helps implement regulated reporting, and is updated periodically to reflect new or revised data identifiers and clarifications.

General information

• Status: Revised (Digital Annex / supplement to SAE J1979).
• Publication date: April 29, 2025 (revision J1979DA_202504).
• Publisher: SAE International.
• ICS / categories: Road vehicle engineering — ICS 43.040 (road vehicle systems) and related diagnostic/test equipment categories.
• Edition / version: 2025 revision (product code J1979DA_202504; part of the J1979 document set).
• Number of pages: Digital annex (supplement) — page count varies by release; SAE product listing shows a digital file (file size ~3.7 MB) for the April 29, 2025 revision. The companion main standard SAE J1979 (E/E Diagnostic Test Modes) is published in a longer main document (example recent J1979 editions are ~143 pages).

Scope

Specifies the Digital Annex that supplements SAE J1979 by defining and maintaining a registry of diagnostic data identifiers (PIDs and other data elements) used for emissions‑related OBD communications between vehicles and external test equipment. The annex is intended to be globally applicable to regulated emissions and propulsion‑related OBD, to support harmonized requests/responses, timing, and presentation-layer mappings used in vehicle diagnostics.

Key topics and requirements

• Registry of regulated emissions and propulsion-related data identifiers (PIDs) and associated metadata (units, resolution, ranges, identifiers).
• Machine-readable annex entries to support tool interoperability and automated updates.
• Alignment with SAE J1979 (application layer) and ISO 15031-5 semantics and mappings for OBD.
• Behavioral expectations for vehicle and external test equipment when data are unavailable or unsupported.
• Support for multiple transport/data link protocols through defined presentation-layer parameters and identifiers (enabling use over CAN, DoCAN, K-Line, etc.).
• Periodic revision and maintenance process to add new identifiers, corrections, and clarifications required by regulators and industry.

Typical use and users

Used by vehicle OEM engineering teams, ECU and telematics suppliers, diagnostic tool and scan‑tool vendors, emissions test houses, regulatory bodies, and aftermarket service equipment developers to ensure consistent interpretation and interchange of OBD diagnostic data. The annex is particularly useful for tool developers implementing standardized PIDs and for organizations that must track regulated emissions‑related data definitions across model years and regions.

Related standards

Directly related to SAE J1979 (E/E Diagnostic Test Modes) and ISO 15031-5 (emissions-related diagnostic services). Also commonly used alongside ISO 15031 series, ISO 14229 (UDS), ISO 15765 (CAN transport), SAE J1930, SAE J1962, SAE J1978 (scan tool), and ISO 27145 (WWH‑OBD) specifications for broader diagnostic, connector, transport and session-layer interoperability.

Keywords

OBD, J1979, J1979-DA, Digital Annex, PIDs, data identifiers, diagnostic test modes, emissions diagnostics, SAE International, ISO 15031, vehicle diagnostics.

FAQ

Q: What is this standard?

A: J1979-DA is the Digital Annex (supplement) to SAE J1979 (E/E Diagnostic Test Modes). It provides a structured, maintainable registry of diagnostic data identifiers and related metadata used for emissions‑related OBD communications.

Q: What does it cover?

A: It catalogs PIDs/data identifiers, units, resolutions and presentation details used by external test equipment and vehicle ECUs for emissions and propulsion related diagnostics, and documents updates and clarifications to support interoperability.

Q: Who typically uses it?

A: Vehicle OEMs, ECU and diagnostic tool vendors, test laboratories, regulatory agencies, and aftermarket diagnostic-equipment manufacturers use the annex to ensure consistent implementation of OBD data reporting.

Q: Is it current or superseded?

A: The Digital Annex was revised April 29, 2025 (product code J1979DA_202504) and is published as a revised supplement; users should check SAE Mobilus or SAE product listings for later revisions or errata.

Q: Is it part of a series?

A: Yes — it is part of the SAE J1979 document set and aligns with ISO 15031-5 and related diagnostic/transport/session standards (ISO 14229, ISO 15765, ISO 15031 series). The DA (Digital Annex) is specifically the machine-readable supplement to the main J1979 specification.

Q: What are the key keywords?

A: OBD, PIDs, data identifiers, digital annex, diagnostic test modes, emissions diagnostics, SAE J1979, ISO 15031.