ISO 15765-4:2021

Road vehicles — Diagnostic communication over Controller Area Network (DoCAN) — Part 4: Requirements for emissions-related systems

This document specifies requirements for CAN-based communication systems between the in-vehicle network and the diagnostic link connector of the vehicle. This document does not specify any requirements related to the in-vehicle CAN network architecture. This document specifies the requirements to enable the in-vehicle CAN-based communication systems to establish, maintain, and terminate communication with the devices connected to the diagnostic link connector.

Véhicules routiers — Diagnostic sur gestionnaire de réseau de communication (DoCAN) — Partie 4: Exigences applicables aux systèmes associés aux émissions

General Information

• Status: Published
• Publication Date: 29-Jul-2021
• ICS: 43.040.15 - Car informatics. On board computer systems
• ICS: 43.180 - Diagnostic, maintenance and test equipment
• Technical Committee: ISO/TC 22/SC 31 - Data communication
• Drafting Committee: ISO/TC 22/SC 31/WG 2 - Vehicle diagnostic protocols
• Current Stage: 6060 - International Standard published
• Start Date: 30-Jul-2021
• Due Date: 29-Apr-2022
• Completion Date: 30-Jul-2021

Relations

• Revises: ISO 15765-4:2016 - Road vehicles — Diagnostic communication over Controller Area Network (DoCAN) — Part 4: Requirements for emissions-related systems
• Effective Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15765-4
Fourth edition
2021-07
Road vehicles — Diagnostic
communication over Controller Area
Network (DoCAN) —
Part 4:
Requirements for emissions-related
systems
Véhicules routiers — Diagnostic sur gestionnaire de réseau de
communication (DoCAN) —
Partie 4: Exigences applicables aux systèmes associés aux émissions
Reference number
©
ISO 2021
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
4.1 Symbols . 2
4.2 Abbreviated terms . 3
5 Conventions . 4
6 Application . 4
6.1 Vehicle communication initialisation sequence . 4
6.1.1 OBDonUDS protocol identification . 4
6.1.2 OBDonEDS protocol identification . 4
6.1.3 Others . 4
6.2 External test equipment communication initialisation sequence . 4
6.3 Bit rate validation procedure . 5
6.3.1 bitrateRecord . 5
6.3.2 Bit rate validation . 5
6.3.3 External test equipment error detection provisions . 6
6.4 CAN identifier validation procedure . 7
6.4.1 CAN identifier validation procedure OBDonEDS . 7
6.4.2 CAN identifier validation procedure OBDonUDS . 9
6.5 Support of ECUNAME reporting.11
7 Application layer (AL) .11
8 Session layer (SL) .12
9 Transport layer (TL) .12
10 Network layer (NL) .12
10.1 General .12
10.2 Parameter definitions .12
10.2.1 Timing parameter values .12
10.2.2 Definition of flow control parameter values .13
10.2.3 Maximum number of OBDonUDS or OBDonEDS ECUs .14
10.3 Addressing formats .15
10.3.1 Normal and normal fixed addressing format .15
10.3.2 Functional addressing .15
10.3.3 Physical addressing .15
10.4 CAN identifier requirements .16
10.4.1 External test equipment .16
10.4.2 OBDonUDS or OBDonEDS server/ECU .16
10.5 Mapping of diagnostic addresses .16
10.5.1 OBDonUDS/OBDonEDS CAN identifiers .16
10.5.2 11-bit CAN identifiers .17
10.5.3 29-bit CAN identifiers .18
11 Data link layer (DLL) .18
12 Physical layer (PHY) .18
12.1 General .18
12.2 Bit rates .19
12.3 CAN bit timing .19
12.3.1 Parameter values .19
12.3.2 Nominal bit rate 250 kbit/s .20
12.3.3 Nominal bit rate 500 kbit/s .20
12.4 External test equipment .21
12.4.1 Electrical parameters .21
12.4.2 Cable parameters . .24
Bibliography .25
iv © ISO 2021 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,
Data communication.
This fourth edition cancels and replaces the third edition (ISO 15765-4:2016), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— changed all time-related parameters to t ;
Parameter_Name
— corrected all occurrences of ⊣⫤ P2 and changed to Δt ;
CAN_max P2_CAN_Client_Max
— Clause 6 title has been changed to application;
— subclause 6.1 title has been changed to vehicle communication initialisation sequence;
— subclause 6.2 title has been changed to external test equipment communication initialisation
sequence;
— changed N_As to t and changed timeout value to 33 ms;
N_As
— changed N_Ar to t and changed timeout value to 33 ms;
N_Ar
— added clarification in 10.3.3 regarding the acceptance of physically addressed request messages.
A list of all parts in the ISO 15765 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
Introduction
This document has been established in order to define common requirements for vehicle diagnostic
systems implemented on a contr
...