ISO 15031-5:2015

Overview

ISO 15031-5:2015 - "Road vehicles - Communication between vehicle and external equipment for emissions-related diagnostics - Part 5: Emissions-related diagnostic services" - defines the diagnostic services, message formats and timing rules used by motor vehicles and external test equipment to exchange emissions-related OBD (On‑Board Diagnostic) data. Designed to meet data reporting needs of OBD regulations in the United States, Europe and other regions, this third‑edition (2015) standard provides the mechanisms for retrieving emission-related information without interpreting country‑specific regulatory applicability.

Key Topics and Technical Requirements

• Diagnostic services and PIDs: Specifies a set of diagnostic services (e.g., Service 01 - current powertrain data, Service 02 - freeze frame, Service 03 - emission‑related DTCs, Services 04–09) with the content of request/response messages.
• Message formats and addressing: Defines request/response message structures, header and data byte conventions, maximum message lengths and functional addressing for ISO 9141‑2, ISO 14230‑4, SAE J1850 and ISO 15765‑4 transports.
• Timing and sequencing: Establishes timing requirements between external test equipment requests and vehicle responses, minimum inter‑request intervals, and multi‑response handling.
• Behavioral rules for unavailable data: Describes how both vehicle and external test equipment must behave when data are not available or invalid.
• Byte order and expansion: Clarifies byte‑order conventions, allowance for future expansion and enhanced diagnostic services.
• References and definitions: References SAE J1979‑DA for PID, OBDMID, TID and INFOTYPE definitions; supersedes or augments details from ISO 9141‑2, ISO 14230‑4, SAE J1850 and ISO 15765‑4 where specified.

Applications and Who Uses It

ISO 15031-5 is used by organizations that design, implement or validate emissions diagnostics and OBD communication:

• Automotive OEMs - integrate OBD diagnostic services into vehicle ECUs.
• Diagnostic tool and scan‑tool manufacturers - implement standard request/response messages and timing to retrieve emissions data.
• Vehicle test labs and certification bodies - gather regulated emissions data during compliance testing.
• Aftermarket service tool developers and repair shops - read/clear emission‑related DTCs and monitor vehicle status.
• Software developers and telematics providers - implement OBD data collection, remote diagnostics and fleet emissions monitoring.

Note: ISO 15031‑5 supports multiple regional requirements but does not interpret specific regulations; users must verify applicability for a given vehicle, engine, model year and region.

Related Standards

• ISO 15031‑4 (external test equipment requirements)
• ISO 9141‑2, ISO 14230‑4, SAE J1850, ISO 15765‑4 (transport layers)
• SAE J1979 (Digital Annex for PIDs and identifiers)

Keywords: ISO 15031-5, OBD, emissions diagnostics, diagnostic services, message formats, SAE J1979, ISO 15765-4, vehicle diagnostics.