ISO 27145-6:2023

Overview - ISO 27145-6:2023 (WWH-OBD External Test Equipment)

ISO 27145-6:2023 specifies the requirements for external test equipment used to communicate with World‑Wide Harmonized On‑Board Diagnostics (WWH‑OBD) equipped vehicles. It defines the minimum capabilities and diagnostic services that external tools must provide to exercise the application‑layer services in ISO 27145‑3 (based on ISO 14229 UDS). The 2023 second edition updates and clarifies requirements (for example, cable length and wording) and ensures safe integration of optional, non‑WWH‑OBD functions without adversely affecting vehicles or equipment.

Key technical topics and requirements

• Communication architecture: Aligns services with the OSI model; maps application, presentation, session, transport, network, data link and physical layers to WWH‑OBD references (ISO 27145‑2/3/4, ISO 14229, ISO 15765, ISO 13400, ISO 11898, IEEE 802.3).
• Diagnostic services and addressing: Defines how external test equipment shall implement UDS‑based diagnostic services and addressing methods to exercise vehicle functions in ISO 27145‑3.
• Clusters of requirements: Minimum capabilities grouped into clusters such as mechanical, electrical, communication setup and connections, and diagnostic messages (including timing, negative response handling, no‑response error handling).
• ECU and DTC handling: Requirements for setting up ECU lists, reading and clearing DTCs, and organizing data information lists.
• Use‑case specific tools: Separate implementation considerations for roadside check, inspection & maintenance (I/M), and repair‑shop test equipment.
• Safety and interoperability: External functions not covered by ISO 27145‑3 must not interfere with WWH‑OBD timing requirements or vehicle safety; applicability may vary by local legislation.
• Multiple tool interactions: Behavioural rules when several test devices communicate with a vehicle.

Practical applications and who uses ISO 27145-6

• Diagnostic tool manufacturers designing external test equipment for passenger cars, commercial vehicles and heavy‑duty applications.
• Automotive OEMs and Tier‑1 suppliers validating OBD communication and interoperability.
• Repair shops, I/M centres and roadside inspection services implementing compliant diagnostic workflows.
• Regulators and test labs verifying conformance to WWH‑OBD Global Technical Regulations.
• Software developers of diagnostic applications (DoCAN, DoIP) ensuring correct session, transport and application‑layer behavior.

Related standards (select)

• ISO 27145 series (Parts 2, 3, 4, 6)
• ISO 14229‑1/‑2 (UDS)
• ISO 15765 (CAN transport)
• ISO 13400 (DoIP)
• ISO 11898 (CAN)
• SAE J1939, SAE J1979, SAE J2012

Keywords: ISO 27145-6, WWH‑OBD, external test equipment, vehicle diagnostics, on‑board diagnostics, diagnostic services, DoIP, DoCAN, UDS.