ISO 15765-2-2024 PDF

Full title and description

Road vehicles — Diagnostic communication over Controller Area Network (DoCAN) — Part 2: Transport protocol and network layer services. This international standard (ISO 15765-2:2024, Edition 4) defines the ISO-TP transport protocol and network-layer services used for diagnostic communication over CAN networks, tailored for CAN-based vehicle network systems and intended to support application-layer diagnostic services such as UDS.

Abstract

This document specifies a transport and network layer protocol with transport and network layer services tailored to meet the requirements of CAN-based vehicle network systems (as specified in ISO 11898-1). The DoCAN protocol provides the transport primitives used by diagnostic application protocols (notably UDS/ISO 14229-series) and supports use cases including enhanced diagnostics, emissions-related OBD, WWH-OBD and end-of-life activation of pyrotechnic devices. The transport protocol defines unconfirmed communication and is written to be applicable to both Classical CAN and CAN FD environments (implementation choices for CAN CC or CAN FD are left to referencing standards).

General information

• Status: Published.
• Publication date: April 2024 (Edition 4, published 2024-04 / 5 April 2024 in catalog listings).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 43.180 (Diagnostic, maintenance and test equipment); 43.040.15 (Car informatics, on-board computer systems).
• Edition / version: 4 (2024).
• Number of pages: 47 (official ISO publication page shows 47 pages).

Scope

Specifies a transport and network layer protocol (DoCAN / ISO-TP) for diagnostic communication over controller area networks. The standard defines the protocol control information (PCI) formats, single- and multi-frame message handling, sequencing (flow control), timing parameters, addressing modes (normal and extended addressing), and network-layer services required by diagnostic application layers on CAN-based networks. It is intended to be referenced by application-level diagnostic standards (UDS, OBD, WWH-OBD) and by national/regulatory specifications where diagnostic transport over CAN is required.

Key topics and requirements

• ISO-TP frame types and Protocol Control Information (PCI) formats for single-frame, first-frame, consecutive-frame and flow-control frames.
• Mechanisms for multi-frame segmentation and reassembly, sequence number management and flow-control handling.
• Timing and timer parameters (P1/P2 style timers) and retransmission/timeout behaviours relevant to diagnostic sessions.
• Addressing modes for CAN (Normal and Extended addressing) and implications for payload length.
• Guidance to support Classical CAN and CAN FD; the standard does not itself mandate which CAN variant must be used by referencing documents.
• Designed to interoperate with application-layer protocols such as ISO 14229-2 (UDS), ISO 15031 / SAE J1979 (OBD), ISO 27145 (WWH-OBD) and ISO 26021 (end-of-life pyrotechnic activation).

Typical use and users

Engineers and architects designing automotive communication stacks (ECU suppliers, Tier-1s), diagnostic tool vendors and test tool developers, vehicle integrators, regulatory bodies specifying on-board diagnostic behaviour, and software developers implementing UDS and diagnostic services on CAN/CAN FD platforms. The standard is used both for embedded ECU firmware transport-layer implementations and for diagnostic application/tool interoperability testing.

Related standards

ISO 15765-2 is part of the ISO 15765 DoCAN family; related documents and referenced standards include ISO 15765-1 (general information and use cases), ISO 15765-3 / ISO 14229 series (UDS — application-layer diagnostic services; note historical transitions where ISO 15765-3 functionality has been superseded by the ISO 14229 family), ISO 15765-4 (emissions-related requirements), ISO 11898-1 (CAN data link/physical layer), ISO 14229-2 (UDS interface primitives), ISO 15031 and SAE J1979 (OBD diagnostics), ISO 27145 (WWH-OBD) and ISO 26021 (end-of-life activation). Implementers should consult these documents for application-layer semantics and regulatory requirements.

Keywords

DoCAN, ISO-TP, ISO 15765-2, transport protocol, CAN, CAN FD, diagnostic communication, UDS, ISO 14229, OBD, segmentation, flow control.

FAQ

Q: What is this standard?

A: ISO 15765-2:2024 defines the transport protocol and network-layer services for diagnostic communication over CAN (commonly referred to as ISO-TP). It standardises how diagnostic messages are segmented, transmitted, flow-controlled and reassembled across CAN networks.

Q: What does it cover?

A: It covers message framing (single/multi-frame), PCI formats, addressing modes, timing and retransmission behavior, flow-control procedures and network-layer services required by diagnostic application protocols running on top of CAN. It also clarifies applicability to Classical CAN and CAN FD while leaving implementation choices for referencing standards.

Q: Who typically uses it?

A: ECU and software developers, diagnostic tool manufacturers, Tier‑1 suppliers, vehicle integrators and standards/regulatory bodies that require interoperable diagnostic transport over CAN networks. Test houses performing interoperability testing and compliance verification also rely on this standard.

Q: Is it current or superseded?

A: Current. ISO 15765-2:2024 (Edition 4) is the published, up-to-date edition (April 2024) and replaces the earlier 2016 edition.

Q: Is it part of a series?

A: Yes. It is Part 2 of the ISO 15765 series (DoCAN). Related parts and neighbouring standards cover general information (Part 1), application-layer diagnostic services (historically Part 3 / now covered by ISO 14229 for UDS), and emissions-related requirements (Part 4), among others.

Q: What are the key keywords?

A: ISO-TP, DoCAN, transport protocol, CAN, CAN FD, diagnostic communication, segmentation, flow control, UDS (ISO 14229), OBD.