Introduction
Vehicle diagnostic communication has been developed starting with the introduction of the rst legislated
emissions-related diagnostics and has evolved over the years, now covering various use cases ranging
from emissions-related diagnostics to vehicle manufacturer specic applications like calibration or electronic
component software updates.
With the introduction of new in-vehicle network communication technologies the interface between the vehicle’s
electronic control units and the external test equipment has been adapted several times to address the specic
characteristics of each new network communication technology requiring optimized data link layer denitions
and transport protocol developments in order to make the new in-vehicle networks usable for diagnostic
communication.
With increasing memory size of electronic control units and the demand to update this increasing amount of
software and an increasing number of functions provided by these control units, technology of the connecting
network and buses has been driven to a level of complexity and speed similar to computer networks. New
applications (x-by-wire, infotainment) require high band-width and real time networks (like FlexRay, MOST)
which cannot be adapted to provide the direct interface to a vehicle. This requires gateways to route and
convert messages between the in-vehicle networks and the vehicle interface to external test equipment.
The intent of ISO 13400 (all parts) is to describe a standardized vehicle interface which
— separates in-vehicle network technology from the external test equipment vehicle interface requirements
to allow for a long-term stable external vehicle communication interface,
— utilizes existing industry standards to dene a long-term stable state-of-the-art communication standard
usable for legislated diagnostic communication as well as for manufacturer-specic use cases, and
— can be easily adapted to new physical and data link layers, including wired and wireless connections using
existing adaptation layers.
To achieve this, all parts of ISO 13400 are based on the Open Systems Interconnection (OSI) Basic Reference
Model specied in ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication systems into seven
layers. Where mapped on this model, the services specied by ISO 14229-1, ISO 14229-2 and ISO 14229-5
are divided into
a) unied diagnostic services (layer 7), specied in ISO 14229-1, ISO 14229-5 and ISO 27145-3,
b) presentation (layer 6):
1) for enhanced diagnostics, specied by the vehicle manufacturer;
2) for WWH-OBD (World-Wide Harmonized On-Board Diagnostics), specied in ISO 27145-2,
SAE J1930-DA, SAE J1939:2011, Appendix C (SPNs), and SAE J1939-73:2010, Appendix A (FMI),
SAE J1979-DA, SAE J2012-DA,
c) session layer services (layer 5), specied in ISO 14229-2,
d) transport protocol (layer 4), specied in ISO 13400-2,
e) network layer (layer 3) services, specied in ISO 13400-2, and
f) physical and data link services (layers 1 and 2), specied in ISO 13400-3,
in accordance with Table 1.
ISO 13400-1:2011(E)
© ISO 2011 – All rights reserved v
