ISO 27145-2:2012

Overview

ISO 27145-2:2012 specifies the common data dictionary for World-Wide Harmonized On-Board Diagnostics (WWH-OBD) communication. As Part 2 of the ISO 27145 series, it defines the regulatory data elements that external test equipment uses to obtain the diagnostic status of a vehicle’s on-board diagnostics (VOBD) system. The standard covers the structure and semantics of diagnostic trouble codes (DTCs), data identifiers (DIDs) and routine identifiers (RIDs), and the mapping from parameter identifiers (PIDs), monitor identifiers (MIDs) and info type identifiers (ITIDs).

Keywords: ISO 27145-2:2012, WWH-OBD, common data dictionary, DTC, DID, RID, VOBD, vehicle diagnostics.

Key topics and requirements

• Regulatory data elements: Defines DTCs, DIDs and RIDs used for regulatory WWH-OBD communication.
• Mapping and interoperability: Describes mapping from PIDs, MIDs and ITIDs to the ISO 27145 data elements to ensure consistent interpretation by external test equipment.
• Presentation layer requirements: Specifies presentation conventions for data exchange (referencing SAE documents such as SAE J1930-DA, SAE J1979-DA, SAE J2012-DA and SAE J1939).
• Data record and layout rules: Details DID/RID data record structures and diagnostic trouble code range/layout conventions used by VOBD servers/ECUs.
• Migration and multi-link support: Designed to be the single worldwide communication standard for OBD-related information while supporting a smooth migration via two data links (ISO 15765-4 DoCAN and ISO 13400 DoIP).
• Extensibility process: Anticipates future WWH-OBD GTR modules and points to SAE digital annex revision procedures for adding new data definitions.

Applications and who uses it

ISO 27145-2 is used by:

• Vehicle manufacturers (OEMs) to implement harmonized OBD reporting for global regulatory compliance.
• Automotive diagnostic tool and test equipment vendors to build generic external testers that read and interpret VOBD data.
• ECU and gateway suppliers to standardize diagnostic data exposure in vehicles.
• Regulatory agencies and test labs to define and validate emissions and OBD conformance.
• Standards and integration engineers working on UDS (ISO 14229) and network-layer implementations.

Practical uses include reading regulatory DTCs, retrieving standardized DIDs/RIDs, implementing presentation-layer conventions, and ensuring consistency across DoCAN and DoIP communication channels.

Related standards

• ISO 27145 series (Parts 1–4; Part 3: message dictionary, Part 4: connection)
• ISO 14229 (Unified Diagnostic Services / UDS)
• ISO 15765-4 and ISO 13400 (transport/network for DoCAN and DoIP)
• SAE J1979-DA, SAE J2012-DA, SAE J1930-DA, SAE J1939 (digital annexes and DTC/SPN definitions)

ISO 27145-2:2012 is essential for anyone implementing or using WWH-OBD-compliant vehicle diagnostics and for achieving consistent, global access to vehicle OBD information.