ISO 11992-4:2014

Road vehicles — Interchange of digital information on electrical connections between towing and towed vehicles — Part 4: Diagnostic communication

ISO 11992-4:2014 specifies the diagnostic communication over a CAN between the towing and towed vehicle(s) of a commercial vehicle and its trailer(s), according to ISO 11992-2 or ISO 11992-3, which allows a diagnostic tester (client) to control diagnostic functions in an on-vehicle ECU (server) embedded in a road vehicle using the communication gateways between the vehicles. It defines the data link layer's specific implementation of the unified diagnostic communication requirements, mainly given in the ISO 14229 and ISO 15765 document series by additional requirements and restrictions specific to the implementation of UDS on an ISO 11992 network. ISO 11992-4:2014 does not apply to any non-diagnostic message transmission use of the communication data link between two ECUs.

Véhicules routiers — Échange d'informations numériques sur les connexions électriques entre véhicules tracteurs et véhicules tractés — Partie 4: Communication de diagnostic

General Information

• Status: Withdrawn
• Publication Date: 24-Apr-2014
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ISO/TC 22/SC 31 - Data communication
• Drafting Committee: ISO/TC 22/SC 31/WG 4 - Network applications
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 14-Apr-2023

Relations

• Revised: ISO 11992-4:2023 - Road vehicles — Interchange of digital information on electrical connections between towing and towed vehicles — Part 4: Diagnostic communication
• Effective Date: 23-Apr-2020
• Revises: ISO 11992-4:2005 - Road vehicles — Interchange of digital information on electrical connections between towing and towed vehicles — Part 4: Diagnostics
• Effective Date: 22-Aug-2009

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11992-4
Second edition
2014-05-01
Road vehicles — Interchange of digital
information on electrical connections
between towing and towed vehicles —
Part 4:
Diagnostic communication
Véhicules routiers — Échange d’informations numériques sur
les connexions électriques entre véhicules tracteurs et véhicules
tractés —
Partie 4: Communication de diagnostic
Reference number
ISO 11992-4:2014(E)
©
ISO 2014

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ISO 11992-4:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

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ISO 11992-4:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 General definitions . 3
5.1 Conventions . 3
5.2 Network components . 3
5.3 Use case definitions . 3
5.4 Diagnostic applications. 4
5.5 Vehicle network architecture . 5
5.6 Diagnostic communication channels . 6
6 Unified diagnostic services implementation . 7
6.1 General . 7
6.2 Overview on diagnostic services . 7
6.3 Non-applicable or restricted services . 8
6.4 Basic diagnostic services . 9
6.5 Enhanced diagnostic services .12
7 Application layer requirements .12
7.1 Application layer services .12
7.2 Application layer protocol .12
7.3 Timing definition .13
8 Presentation layer requirements .14
9 Session layer requirements .14
10 Transport layer requirements.14
10.1 General .14
10.2 Transport layer service parameters .14
11 Network layer requirements.15
11.1 General .15
11.2 Message routing .15
11.3 Establishing, maintaining, and terminating of connections .16
11.4 Diagnostic communication channels (DCC).16
11.5 Mixed addressing network layer service parameter .17
11.6 Subnet addressing network layer service parameter.18
11.7 Network layer protocol timing .22
12 Data link layer requirements
.22
12.1 General .22
12.2 Mapping for mixed addressing .22
12.3 Mapping for subnet addressing .23
13 Physical layer requirements .23
Annex A (normative) Basic diagnostic service parameters .24
Annex B (normative) Address definitions .29
Annex C (informative) Message routing examples.31
Bibliography .35
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ISO 11992-4:2014(E)

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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical
and electronic equipment.
This second edition cancels and replaces the first edition (ISO 11992-4:2005), which has been technically
revised. It also incorporates ISO 11992-4:2005/Cor1:2006.
ISO 11992 consists of the following parts, under the general title Road vehicles — Interchange of digital
information on electrical connections between towing and towed vehicles:
— Part 1: Physical layer and data-link layers
— Part 2: Application layer for brakes and running gear
— Part 3: Application layer for equipment other than brakes and running gear
— Part 4: Diagnostic communication
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ISO 11992-4:2014(E)

Introduction
This part of ISO 11992 has been established in order to define the implementation of a diagnostic data
interchange between a commercial vehicle and its towed vehicle(s), including communication between
towed vehicles, using a Controller Area Network (CAN) data link according to ISO 11992-1 and based on
the definitions for unified diagnostic services and their implementation on CAN given in the ISO 14229
and ISO 15765 document series.
To achieve this, the document is based on the Open Systems Interconnection (OSI) Basic Reference
Model, in accordance with ISO/IEC 7498-1 and ISO/IEC 10731, which structures the communication
systems into seven layers. When mapped on this model, the services used by a diagnostic tester (client)
and an Electronic Control Unit (ECU, server) based on this document are broken into the following layers
according to Table 1:
— application layer (layer 7), based on ISO 11992-4, ISO 14229-1, and ISO 14229-3;
— presentation layer (layer 6), vehicle manufacturer/system supplier specific or ISO 22901, ODX;
— session layer services (layer 5), based on ISO 11992-4 and ISO 14229-2;
— transport layer services (layer 4), based on ISO 11992-4 and ISO 15765-2;
— network layer services (layer 3), based on ISO 11992-4 and ISO 15765-2;
— data link layer (layer 2), specified in ISO 11898-1;
— physical layer (layer 1), specified in ISO 11992-1.
This document does not include any redundant information of the documents listed in this introduction.
It focuses on
— additional requirements specific to the implementation of UDS on an ISO 11992 network and
— specific restrictions in the implementation of UDS on an ISO 11992 network.
In case of any contradictions, the definitions given in this document take precedence.
Table 1 — International Standards applicable to the OSI layers
Applicability OSI seven layers Diagnostics services on the communication between the com-
mercial vehicles and their towed vehicles
seven layers application (layer 7) ISO 11992-4, ISO 14229-1, ISO 14229-3
according to
presentation (layer 6) vehicle manufacturer specific or ISO 22901
ISO/IEC 7498-1
and ISO/ session (layer 5) ISO 11992-4, ISO 14229-2
IEC 10731
transport (layer 4) ISO 11992-4, ISO 15765-2
network (layer 3) ISO 11992-4, ISO 15765-2
data link (layer 2) ISO 11898-1
physical (layer 1) ISO 11992-1
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INTERNATIONAL STANDARD ISO 11992-4:2014(E)
Road vehicles — Interchange of digital information
on electrical connections between towing and towed
vehicles —
Part 4:
Diagnostic communication
1 Scope
This part of ISO 11992 specifies the diagnostic communication over a CAN between the towing and
towed vehicle(s) of a commercial vehicle and its trailer(s), according to ISO 11992-2 or ISO 11992-3,
which allows a diagnostic tester (client) to control diagnostic functions in an on-vehicle ECU (server)
embedded in a road vehicle using the communication gateways between the vehicles.
It defines the data link layer’s specific implementation of the unified diagnostic communication
requirements, mainly given in the ISO 14229 and ISO 15765 document series by additional requirements
and restrictions specific to the implementation of UDS on an ISO 11992 network.
This part of ISO 11992 does not apply to any non-diagnostic message transmission use of the
communication data link between two ECUs.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 11992-1, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 1: Physical and data-link layers
ISO 14229-1:2013, Road vehicles — Unified diagnostic services (UDS) — Part 1: Specification and
requirements
ISO 14229-2:2013, Road vehicles — Unified diagnostic services (UDS) — Part 2: Session layer services
ISO 14229-3:2012, Road vehicles — Unified diagnostic services (UDS) — Part 3: Unified diagnostic services
on CAN implementation (UDSonCAN)
ISO 15031-6, Road vehicles — Communication between vehicle and external equipment for emissions-
related diagnostics — Part 6: Diagnostic trouble code definitions
ISO 15765-1:2011, Road vehicles — Diagnostic communication over Controller Area Networks (DoCAN) —
Part 1: General information and use case definition
ISO 15765-2:2011, Road vehicles — Diagnostic communication over Controller Area Networks (DoCAN) —
Part 2: Transport protocol and network layer services
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11992-1, ISO 14229-1,
ISO 14229-2, ISO 14229-3, ISO 15765-1, and ISO 15765-2 apply.
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ISO 11992-4:2014(E)

4 Symbols and abbreviated terms
For the purposes of this International Standard, the following abbreviated terms apply.
A_AE application layer address extension
A_Mtype application layer message type
A_SA application layer source address
A_TA application layer target address
BS block size
CAN Controller Area Network
CAN-ID CAN identifier
Cvt convention
DCC diagnostic communication channel
DID data identifier
DLC data length code
DP data page
DTC Diagnostic Trouble Code
ECU Electronic Control Unit
EDP extended data page
FS flow status
N_AE network layer address extension
N_AI network layer address information
N_SA network layer source address
N_TA network layer target address
N_TAtype network layer target address type
N_WFTmax network layer maximum number of wait frames
N_Subnet width of the subnet mask used for subnet addressing
P priority
PDU Protocol Data Unit
PF parameter format
PGN parameter group number
PS parameter specific
SID service identifier
STmin separation time
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ISO 11992-4:2014(E)

5 General definitions
5.1 Conventions
This International Standard is based on the conventions used in ISO 14229-1 and the underlying OSI
Service Conventions (ISO/IEC 10731:1994) as they apply for diagnostic services.
These conventions specify the interactions between the service user and the service provider. The
information is passed between the service user and the service provider by the service primitives,
which can convey parameters.
5.2 Network components
5.2.1 Diagnostic network
The diagnostic network, as a whole, contains all clients and servers that can communicate with each
other on the different vehicles of a road train, as well as the diagnostic gateways between the vehicles.
5.2.2 Diagnostic subnetwork
All the clients and servers of a subnetwork are connected to the same vehicle’s diagnostic network.
Subnetworks are separated by the gateways between the vehicles.
5.2.3 Diagnostic gateway
A diagnostic gateway is a node in the network that is physically connected to two (or more) subnetworks
and has the ability to transfer diagnostic messages between the subnetworks.
5.3 Use case definitions
5.3.1 General
This section lists the individual use cases that will be covered by the diagnostic communication over the
ISO 11992 protocol at the following areas:
— vehicle/ECU engineering (development);
— vehicle/ECU manufacturing (production plant, assembly line);
— service (dealership, aftermarket repair shop);
— retrieval of information between connected vehicles.
The following use cases are supported by the communication protocol.
5.3.2 Use case 1 — Driver information
Driver information specifies the use case to enable an in-vehicle information retrieval system at the
commercial vehicle to qualify the readiness of the towed vehicle(s).
In this case, usually an information-retrieval entity is installed in the commercial vehicle that gets data
from the various ECUs located in the road train, including the towed vehicle(s), and forwards relevant
information about the roadworthiness of the road train to the driver.
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ISO 11992-4:2014(E)

5.3.3 Use case 2 — Vehicle inspection and repair
Vehicle inspection and repair specifies the use case to enable external test equipment connected to the
road train to qualify the readiness of any vehicle and to perform vehicle diagnostic fault tracing as part
of a repair.
In this case, usually the external test equipment is connected to the commercial vehicle and requests
data from the road train that can be qualified to determine the readiness of the vehicle(s) or to perform
vehicle diagnostic fault tracing as part of a repair.
5.3.4 Use case 3 — ECU/vehicle software reprogramming
ECU/vehicle software reprogramming specifies the use case to reprogram the ECU(s) of a towed vehicle
through its data communication channel.
In this case, usually the external programming equipment is connected to the commercial vehicle or
directly to a towed vehicle and uses diagnostic communication to (re)program or configure ECU(s)
located in the towed vehicle.
5.3.5 Use case 4 — ECU/vehicle assembly line inspection and repair
ECU/vehicle assembly line inspection and repair specifies the use case to enable an external test system
connected to a towed vehicle to support the assembly line inspection and repair of the towed vehicle’s
ECU systems.
In this case, usually the external test equipment is connected to the commercial vehicle or directly to
the towed vehicle and uses diagnostic services to determine the readiness of the vehicle(s) or to perform
vehicle diagnostic fault tracing as part of a repair.
5.3.6 Use case 5 — Multipurpose data transfer between vehicles
Multipurpose data transfer between vehicles specifies the use case to enable the ECU(s) in any vehicle of
the road train to retrieve information from other vehicle’s ECU(s).
In this case, an ECU can use diagnostic services to retrieve information from another ECU for various
purposes.
5.4 Diagnostic applications
The diagnostic applications are divided into two types.
— Basic diagnostics:
The purpose of the basic diagnostics is to provide the vehicle’s independent identification and
diagnostic information. All basic diagnostic functions and services shall be provided under all
operation conditions in the default diagnostic session without the need for specific access rights.
— Enhanced diagnostics:
The support and the conditions, under which the enhanced diagnostic functions and services
are provided, are manufacturer/system-supplier specific. It is in the responsibility of the
manufacturer/system supplier to secure a server against unauthorized access and to ensure
performance and safe operation in all operation modes allowing enhanced diagnostics.
The functions, services, and protocols of the OSI layers 1 to 4 shall be identical for basic diagnostics and
enhanced diagnostics. For OSI layers 5 to 7, the implementation of the functions, services, and protocols
are varying according to the definitions given in this document.
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ISO 11992-4:2014(E)

5.5 Vehicle network architecture
This document supports the diagnostic communication between a commercial vehicle and its towed
vehicles as illustrated in Figure 1.
Key
1 truck/commercial vehicle
2 trailer/towed vehicle #1
3 dolly/towed vehicle #2
4 trailer/towed vehicle #3
Figure 1 — Example of a possible road train configuration
Subnet definitions shall be as follows.
— The commercial vehicle’s logical network shall expand over
— all servers and clients located at the commercial vehicle and
— the towed vehicle gateways.
— The physical network segments between each towing and towed vehicle shall be part of the local
logical network of the commercial vehicle and share the logical addressing scheme of the commercial
vehicle.
— Each towed vehicle shall implement its own local logical network(s) with its own addressing scheme.
— Server and client entities that are not located at the same logical network shall be addressed and
identified by means of remote network addressing.
Details about the used addressing scheme are given in Clause 11 (Network layer requirements).
Figure 2 shows an example of the vehicle network architecture.
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ISO 11992-4:2014(E)

Figure 2 — Vehicle network architecture example
5.6 Diagnostic communication channels
This document specifies the diagnostic requests sent from any of the vehicles to any other vehicle of a
road train. For the communication between those vehicles, defined diagnostic communication channels
(DCC) shall be used as specified in Clause 11.
The defined communication channels shall be used as follows.
— For the communication between a client located in the commercial vehicle network and a server
located in a towed vehicle, network DCC11, DCC12, DCC21, and DCC22 shall be used.
— For the communication between a client located in a towed vehicle network and a server located
elsewhere in the road train, DCCX shall be used.
The address mapping between the vehicle networks shall be implemented in the gateway entities and
is specified in this document. Address mapping at the vehicle’s local networks is left open to the system
builder. Examples that are more detailed are given in Annex C.
EXAMPLE Diagnostic communication between a client (test equipment) located at the commercial vehicle
and a server (ECU) located at towed vehicle #1.
An example is given in Figure 3 and Table 2.
Figure 3 — Application layer address mapping example
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ISO 11992-4:2014(E)

Table 2 — Application layer address mapping example
Message A_SA A_TA A_AE
The test equipment sends a remote diagnostic request message. 241 200 62
The gateway at the client side receives the message and forwards it onto the CAN 241 200 62
network between the towing and towed vehicles.
The gateway at the server side receives the message and forwards it onto the server’s 1 62 241
vehicle local bus.
The remote server receives the message and sends back a diagnostic response. 62 1 241
The gateway at the server side receives the message and forwards it onto the CAN 200 241 62
network between the towing and towed vehicles.
The gateway at the client side receives the message and forwards it onto the client’s 200 241 62
vehicle local bus.
6 Unified diagnostic services implementation
6.1 General
This clause defines how the diagnostic services as defined in ISO 14229-1 apply to the diagnostics on
ISO 11992. For each applicable service, the applicable sub-function and data parameters are defined.
6.2 Overview on diagnostic services
The purpose of Table 3 is to reference all unified diagnostic services, as they are applicable for an
implementation of UDS on ISO 11992. The table contains the sum of all applicable services. Certain
applications using this document can restrict the number of useable services and can categorize them in
certain application areas/diagnostic sessions (default session, extended session, etc.).
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ISO 11992-4:2014(E)

Table 3 — Overview of applicable ISO 14229-1 Unified Diagnostic Services
Diagnostic service name SID Specification Document refer-
(ISO 14229-1) value ence
Diagnostic and Communication Management Functional Unit
DiagnosticSessionControl 10 No specific requirements —
16
ECUReset 11 No specific requirements —
16
SecurityAccess 27 No specific requirements —
16
CommunicationControl 28 Restricted use 6.3
16
TesterPresent 3E No specific requirements —
16
AccessTimingParameters 83 Not supported 6.3
16
SecuredDataTransmission 84 No specific requirements —
16
ControlDTCSetting 85 No specific requirements —
16
ResponseOnEvent 86 Not supported 6.3
16
LinkControl 87 Not supported 6.3
16
Data Transmission Functional Unit
ReadDataByIdentifer 22 Data link layer specific definitions exist 6.4.3
16
ReadMemoryByAddress 23 No specific requirements —
16
ReadScalingDataByIdentifier 24 No specific requirements —
16
ReadDataByPeriodicIdentifier 2A Not supported 6.3
16
DynamicallyDefineDataIdentifier 2C No specific requirements —
16
WriteDataByIdentifier 2E No specific requirements —
16
WriteMemoryByAddress 3D No specific requirements —
16
Stored Data Transmission Functional Unit
ReadDTCInformation 19 Data link layer specific definitions exist 6.4.2
16
ClearDiagnosticInformation 14 Data link layer specific definitions exist 6.4.2
16
Input/output Control Functional Unit
InputOutputControlByIdentifier 2F No specific requirements —
16
Remote Activation Of Routine Functional Unit
RoutineControl 31 No specific requirements —
16
Upload/Download Functional Unit
RequestDownload 34 No specific requirements —
16
RequestUpload 35 No specific requirements —
16
TransferData 36 No specific requirements —
16
RequestTransferExit 37 No specific requirements —
16
6.3 Non-applicable or restr
...

DRAFT INTERNATIONAL STANDARD ISO/DIS 11992-4
ISO/TC 22/SC 3 Secretariat: DIN
Voting begins on Voting terminates on

2012-02-21 2012-07-21
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION  •  МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ  •  ORGANISATION INTERNATIONALE DE NORMALISATION


Road vehicles — Interchange of digital information on electrical
connections between towing and towed vehicles —
Part 4:
Diagnostic communication
Véhicules routiers — Échange d'informations numériques sur les connexions électriques entre véhicules
tracteurs et véhicules tractés —
Partie 4: Communication de diagnostic
[Revision of first edition (ISO 11992-4:2005)]
ICS 43.040.15





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the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est
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Secrétariat central de l'ISO au stade de publication.



THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
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RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©  International Organization for Standardization, 2012

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ISO/DIS 11992-4

Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user’s country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,
photocopying, recording or otherwise, without prior written permission being secured.
Requests for permission to reproduce should be addressed to either ISO at the address below or ISO’s
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Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.

ii © ISO 2012 – All rights reserved

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ISO/DIS 11992-4
Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviated terms .6
5 General definitions .7
5.1 Conventions .7
5.2 Use case definitions .7
5.3 Diagnostic applications .9
5.4 Vehicle network architecture .9
5.5 Diagnostic communication channels . 11
6 Application layer requirements . 12
6.1 Application layer services . 12
6.2 Application layer protocol . 12
6.3 Timing definition . 12
6.4 Overview on diagnostic services . 14
6.5 Non-applicable or restricted services . 15
6.6 Basic diagnostic services . 15
6.7 Enhanced diagnostic services . 18
7 Presentation layer requirements . 18
8 Session layer requirements . 18
9 Network layer requirements . 18
9.1 General . 18
9.2 Message routing . 18
9.3 Establishing, maintaining and termination of connections . 18
9.4 Diagnostic communication channels (DCC) . 19
9.5 Network layer service parameter . 19
9.6 Network layer gateway function . 22
9.7 Network layer protocol timing . 22
10 Transport layer requirements . 23
10.1 General . 23
10.2 Transport layer service parameters . 23
11 Data link layer requirements . 24
12 Physical layer requirements . 24
Annex A (normative) Basic diagnostic service parameters . 25
Annex B (normative) Address definitions . 30
Annex C (informative) Message routing examples . 32
Bibliography . 37

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ISO/DIS 11992-4
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 11992-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
ISO 11992 consists of the following parts, under the general title Road vehicles — Interchange of digital
information on electrical connections between towing and towed vehicles:
 Part 1: Physical layer and data-link layer
 Part 2: Application layer for brakes and running gear equipment
 Part 3: Application layer for equipment other than brakes and running gear
 Part 4: Diagnostic communication
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ISO/DIS 11992-4
Introduction
This part of the international standard has been established in order to define the implementation of a
diagnostic data interchange between a commercial vehicle and its towed vehicle(s), including communication
between towed vehicles, using a Controller Area Network (CAN) serial data link according to ISO 11992-1 and
based on the definitions for unified diagnostic services and their implementation on CAN given in the
ISO 14229 and ISO 15765 document series.
To achieve this, the document is based on the Open Systems Interconnection (OSI) Basic Reference Model in
accordance with ISO 7498 and ISO/IEC 10731, which structures communication systems into seven layers.
When mapped on this model, the services used by a diagnostic tester (client) and an Electronic Control Unit
(ECU, server) based on this document are broken into the following layers according to Table 1:
 Application layer (layer 7), based on ISO 14229-1 and ISO 14229-3
 Presentation layer (layer 6), vehicle manufacturer / system supplier specific or ISO 22901 ODX
 Session layer services (layer 5), based on ISO 14229-2
 Transport layer services (layer 4), based on ISO 15765-2
 Network layer services (layer 3), based on ISO 15765-2
 Data link layer (layer 2), specified in ISO 11898-1
 Physical layer (layer 1), specified in ISO 11992-1
This document does not include any redundant information of the documents listed in this introduction. It
focuses on
 additional requirements specific to the implementation of UDS on a ISO 11992 network, and
 specific restrictions in the implementation of UDS on a ISO 11992 network.
In case of any contradictions the definitions given in this document shall have precedence.
Table 1 — International standards applicable to the O.S.I. layers
Applicability OSI 7 layer Diagnostics services on communication
between commercial vehicles and their towed vehicles
Application (layer 7) ISO 11992-4, ISO 14229-1, ISO 14229-3
Presentation (layer 6) vehicle manufacturer specific
Seven layer
Session (layer 5) ISO 11992-4, ISO 14229-2
according to
ISO/IEC 7498 Transport (layer 4) ISO 11992-4, ISO 15765-2
and ISO/IEC
Network (layer 3) ISO 11992-4, ISO 15765-2
10731
Data link (layer 2) ISO 11898-1
Physical (layer 1) ISO 11992-1

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DRAFT INTERNATIONAL STANDARD ISO/DIS 11992-4
Road vehicles — Interchange of digital information on electrical
connections between towing and towed vehicles —
Part 4:
Diagnostic communication
1 Scope
This document specifies the diagnostic communication over CAN on a serial data link between the towing and
towed vehicle(s) of a commercial vehicle and its trailer(s) according to ISO 11992-2 or ISO 11992-3, which
allow a diagnostic tester (client) to control diagnostic functions in an on-vehicle Electronic Control Unit (server)
embedded in a road vehicle using the communication gateways between the vehicles.
It defines the data link layer specific implementation of the unified diagnostic communication requirements
mainly given in the ISO 14229 and ISO 15765 document series by additional requirements and restrictions
specific to the implementation of UDS on an ISO 11992 network.
This document does not apply to any non-diagnostic message transmission use of the communication data
link between two Electronic Control Units.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 11992-2, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 2: Application layer for brakes and running gear
ISO 11992-3, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 3: Application layer for equipment other than brakes and running gear
ISO 14229-1:2011, Road vehicles — Unified diagnostic services (UDS) — Part 1: Specification and
requirements
ISO 14229-2:2011, Road vehicles — Unified diagnostic services (UDS) — Part 2: Session layer services
ISO 14229-3:2011, Road vehicles — Unified diagnostic services (UDS) — Part 3: Unified diagnostic services
on CAN implementation (UDSonCAN)
ISO 15031-6 Road vehicles — Communication between vehicle and external equipment for emissions-related
diagnostics — Part 6: Diagnostic trouble code definitions
ISO 15765-1:2010, Road vehicles — Diagnostic communication over Controller Area Networks (DoCAN) —
Part 1: General information and use case definition
ISO 15765-2:2010, Road vehicles — Diagnostic communication over Controller Area Networks (DoCAN) —
Part 2: Transport protocol and network layer services
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11992-1, ISO 11992-2,
ISO 11992-3, ISO 14229-1, ISO4229-2, ISO 14229-3, ISO-15765-1 and ISO 15765-2 and the following apply.
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ISO/DIS 11992-4
3.1
Diagnostic network
The diagnostic network, as a whole, contains all clients and servers that can communicate with each other on
the different vehicles of a road-train, as well as the diagnostic gateways between the vehicles.
3.2
Diagnostic sub-network
All clients and servers of a sub-network are connected to the same vehicle's diagnostic network. Sub-
networks are separated by the gateways between the vehicles.
3.2
Diagnostic gateway
A diagnostic gateway is a node in the network that is physically connected to two (or more) sub-networks and
has the ability to transfer diagnostic messages between the sub-networks.
4 Symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in ISO 11898-1, ISO 11992-1,
ISO 14229-1, ISO 14229-3 and ISO 15765-2 and the following apply.
A_PDU Application layer protocol data unit
BS block size
CAN Controller area network
CAN-ID CAN identifier
Cvt convention
DCC Diagnostic communication channel
DID Data identifier
DLC Data length code
DP Data page
DTC Diagnostic trouble code
ECU Electronic control unit
EDP Extended data page
FS Flow status
N_AE Network layer address extension
N_AI Network layer address information
N_SA Network layer source address
N_TA Network layer target address
N_TAtype Network layer target address type
N_WFTmax Network layer maximum number of wait frames
P Priority
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ISO/DIS 11992-4
PDU Protocol data unit
PF Parameter format
PGN Parameter group number
PS Parameter specific
RA Remote address
SA Source address
SID Service identifier
STmin Separation time
TA Target address
TA_type Target address type
5 General definitions
5.1 Conventions
This document is based on the conventions used in ISO 14229-1 and the underlying OSI Service Conventions
(ISO/IEC 10731:1994) as they apply for diagnostic services.
These conventions specify the interactions between the service user and the service provider. Information is
passed between the service user and the service provider by service primitives, which may convey
parameters.
5.2 Use case definitions
5.2.1 General
This section lists the individual use cases which will be covered by the diagnostic communication over
ISO 11992 protocol at the following areas:
 Vehicle / ECU engineering (development)
 Vehicle / ECU manufacturing (production plant, assembly line)
 Service (dealership, aftermarket repair shop)
 Retrieval of information between connected vehicles
The following use cases are supported by the communication protocol
5.2.2 Use case 1 – Driver information
Driver information specifies the use case to enable an in-vehicle information retrieval system at the
commercial vehicle to qualify readiness of the towed vehicle(s).
In this case usually an information retrieval entity is installed in the commercial vehicle that gets data from the
various ECUs located in the road train, including the towed vehicle(s), and forwards relevant information about
the road worthiness of the road train to the driver.
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ISO/DIS 11992-4
5.2.3 Use case 2 – Vehicle inspection and repair
Vehicle inspection and repair specifies the use case to enable an external test equipment connected to the
road-train to qualify readiness of any vehicle and to perform vehicle diagnostic fault tracing as part of a repair.
In this case usually an external test equipment is connected to the commercial vehicle and request road train
data which can be qualified to determine the readiness of the vehicle(s) or to perform vehicle diagnostic fault
tracing as part of a repair.
5.2.4 Use case 3 – ECU/vehicle software reprogramming
ECU/vehicle software reprogramming specifies the use case to reprogram the ECU(s) of a towed vehicle
through its data communication channel.
In this case usually an external programming equipment is connected to the commercial vehicle or directly to
a towed vehicle and uses diagnostic communication to (re-)program or configure ECU(s) located in the towed
vehicle.
5.2.5 Use case 4 – ECU/vehicle assembly line inspection and repair
ECU/vehicle assembly line inspection and repair specifies the use case to enable an external test system
connected to a towed vehicle to support the assembly line inspection and repair of towed vehicle ECU
systems.
In this case usually an external test equipment is connected to the commercial vehicle or directly to the towed
vehicle and uses diagnostic services to determine the readiness of the vehicle(s) or to perform vehicle
diagnostic fault tracing as part of a repair.
5.2.6 Use case 5 – Multi-purpose data transfer between vehicles
Multi-purpose data transfer between vehicles specifies the use case to enable ECU(s) in any vehicle of the
road-train to retrieve information from other vehicle's ECU(s).
In this case an ECU may use diagnostic services to retrieve information from another ECU for various
purposes.
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ISO/DIS 11992-4

5.3 Diagnostic applications
The diagnostic applications are divided into two types
 Basic diagnostics
The purpose of the basic diagnostics is to provide vehicle independent identification and diagnostic
information. All basic diagnostic functions and services shall be provided under all operation conditions in
the default diagnostic session without the need for specific access rights.
 Enhanced diagnostics
The support and the conditions under which enhanced diagnostic functions and services are provided are
manufacturer/system supplier specific. It is in the responsibility of the manufacturer/system supplier to
secure a server against unauthorized access and to ensure performance and safe operation in all
operation modes allowing enhanced diagnostics.
Functions, services and protocols of the OSI layers 1 to 4 shall be identical for basic diagnostics and
enhanced diagnostics. For OSI layers 5 to 7 the implementation of functions, services and protocols are
varying according the definitions given in this document.
5.4 Vehicle network architecture
This document supports the diagnostic communication between a commercial vehicle and its towed vehicles
as illustrated in Figure 1.

1 2 3 4

Key:
1 truck / commercial vehicle (position #0)
2 trailer / towed vehicle position #1
3 dolly / towed vehicle position #2
4 trailer / towed vehicle position #3
Figure 1 — Example of a possible road train configuration
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ISO/DIS 11992-4

Subnet definitions shall be as follows
 The commercial vehicle's logical network shall expand over
 all servers and clients located at the commercial vehicle, and
 the towed vehicle gateways
 The physical network segments between each towing and towed vehicle shall be part of the local logical
network of the commercial vehicle and share the logical addressing scheme of the commercial vehicle.
 Each towed vehicle shall implement its own local logical network(s) with its own addressing scheme.
 Server and client entities that are not located at the same logical network shall be addressed and
identified by means of remote network addressing.
Details about the used addressing scheme are given in clause 9 (Network layer ).
Figure 2 shows an example of the vehicle network architecture.
Commercial
Client 1 vehicle logical
network
Commercial Towed Towed
vehicle vehicle #1 vehicle #2
gateway gateway gateway
Server 1 Server 1
Towed Towed
Server 2 Server 1 Server 2
Commercial
vehicle vehicle
vehicle local
local local
network
network network
Server 3 Server 2
Server 4 Server 3
Commercial vehicle Towed vehicle #1 Towed vehicle #2

Figure 2 — Vehicle network architecture example
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ISO/DIS 11992-4

5.5 Diagnostic communication channels
This document specifies diagnostic requests sent from any of the vehicles to any other vehicle of a road-train.
For communication between vehicles defined diagnostic communication channels (DCC) shall be used as
defined in clause 9 based on the service data unit and application layer address mapping specification given
in ISO 14229-1.
An example is given in Figure 3 and Table 2
ISO 11992
DCC
241 (241) 1
test remote
gateway gateway
equipment server
(200) 200 62

Figure 3 — application layer address mapping example

Table 2 — application layer address mapping example
Message SA TA RA
The test equipment sends a remote diagnostic request message 241 200 62
The client gate receives the message and sends it out on the ISO 11992 bus 241 200 62
The server gate receives the message and sends it out on the server's vehicle local bus 1 62 241
The remote server receives the message and sends back a diagnostic response 62 1 241
The server gate receives the message and sends it out on the ISO 11992 bus 200 241 62
The client gate receives the message and sends it out on the client's vehicle local bus 200 241 62

The address mapping between the vehicle networks shall be done by the gateway entities and is specified in
this document. Address mapping at the vehicle's local networks is left open to the system builder. More
detailed examples are given in the (informative) Annex C.
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ISO/DIS 11992-4

6 Application layer requirements
6.1 Application layer services
The application layer services as defined in ISO 14229-1 for client-server based systems shall be used to
perform functions such as test, inspection, monitoring, diagnosis or programming of on-board vehicle servers.
6.2 Application layer protocol
The application layer protocol as defined in ISO 14229-1 shall be used with the parameters defined in Table 3
at peer entity networks.
Table 3 — application layer parameters
Parameter Peer Definition Data range
network
SA_request client Local address of the client Any allowed client address except e.g. the specified
addresses given in Table B.1 — Towing / towed
vehicle data link — Physical addresses
server Local gateway address at Any gateway address according to the definitions
the vehicle the server is given in Table B.3 — Trailer local network —
located on Physical addresses
SA_response client Gateway address at the Any gateway address according to the definitions
given in Table B.1 — Towing / towed vehicle data
vehicle the server is
located on link — Physical addresses
server Local address of the Any allowed server address within the server's
server vehicle network.
TA_request client Gateway address at the Any gateway address according to the definitions
given in Table B.1 — Towing / towed vehicle data
vehicle the server is
located on link — Physical addresses or Table B.2 — Towing /
towed vehicle data link — Functional addresses
server Local address of the Any allowed server address within the server's
server vehicle network.
TA_response client Local address of the client Any allowed client address except e.g. the specified
addresses given in Table B.1 — Towing / towed
vehicle data link — Physical addresses
server Local gateway address at Any gateway address according to the definitions
the vehicle the server is given in Table B.3 — Trailer local network —
located on Physical addresses
RA client Local address of the Any allowed server address within the server's
server vehicle network.
server Local address of the client Any address except the specified addresses given
in Table B.1 — Towing / towed vehicle data link —
Physical addresses
TAtype Target address type to be {   |
used for TA  }

6.3 Timing definition
6.3.1 General
This sub-clause specifies the message timing parameters and how they apply to a client and a server.
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ISO/DIS 11992-4
6.3.2 Message timing parameter values
The message timing parameter values for the default diagnostic session shall be in accordance with
ISO 14229-3 and the deviations specified in Table 4.
Table 4 — Message timing parameters
Timing Definition Minimum Maximum
parameter
ΔP2 The ΔP2 parameter is defined to be the worst case system network 0 ms 200 ms
design-dependent message transmission delays such as delays
introduced by gateways between towing and towed vehicles and bus-
load arbitration delay.
P2
The P2 parameter is a performance requirement for the 0 ms 50 ms
server Server
server/ECU to start with the response message after the reception of
a request message.
P2 P2 + ΔP2 250 ms —
client
server, max max
P2* The P2* parameter is a performance requirement for the server to 0 ms 5 000 ms
server server
start with the response message after the transmission of a negative
response message with the negative response code 78 (enhanced
16
response timing)
P2* P2* + ΔP2 5 200 ms —
client
server, max max

6.3.3 Unsolicited response messages
Unsolicited response messages are not applicable for this document.
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ISO/DIS 11992-4

6.4 Overview on diagnostic services
The purpose of Table 5 is to reference all unified diagnostic services as they are applicable for an
implementation of UDS on ISO 11992. The table contains the sum of all applicable services. Certain
applications using this docum
...