Civil Engineering Reference
In-Depth Information
ISO 27145-2 common data dictionary references the following documents con-
taining emission-related data definitions:
• SAE°J1930-DA, electrical/electronic systems diagnostic terms, definitions, ab-
breviations and acronyms (includes all standardized terms and abbreviations).
• SAE°J1979-DA E/E diagnostic test modes (includes all standardized data items:
PIDs, TIDs, MIDs, ITIDs).
• SAE°J2012-DA, diagnostic trouble codes (includes all standardized DTCs).
• SAE°J1939, top level (includes all standardized SPNs and PGNs).
ISO 27145-3 common message dictionary specifies the implementation of a subset
of ISO 14229-1 UDS diagnostic services.
ISO 14229-2 UDS session layer services define the standardized service primi-
tive interface between the OSI layer 5 (session) and OSI layer 4 (transport). Through
this interface the implementation of the UDS diagnostic services is independent of
the underlying communication protocols (CAN, IP). This is important when the
vehicle manufacturer is required to transition from CAN to Internet protocol based
on future legislation.
Table
4.18
provides an overview of the ISO 15031-5 OBD services and the map-
ping to ISO 27145-3 (ISO 14229-1 UDS) diagnostic services and associated sub-
functions and data ranges.
4.4
SAE J1939
SAE J1939 is a set of standards for both in-vehicle normal ECU to ECU com-
munication protocol and diagnostic communication protocol. The standards cover
relevant OSI layers and specify physical link (cable), how the messages are built
up, NMT, in-vehicle communication with data items, diagnostic communication
with DMs and data, name claiming and conformance test specification. Parts of the
set of standards are used in heavy-duty and medium-duty applications worldwide.
When SAE J1939 was introduced, CAN was not mentioned but it was soon
included. First, the -71 layer was introduced for normal in-vehicle communication
and later the J1939-73 diagnostic layer was introduced.
The protocol is used in HDVs including trailers, agricultural machines, off-road
equipment, boats and stationary engines and it has been discussed for residential
vehicles also. The main reason is that the protocol has been implemented in engine
control modules (ECMs) for medium-duty/heavy-duty diesel engines as a standard.
The situation in the USA is that a truck may be a chassis from an OEM, with an
engine from an engine manufacturer and a transmission from a transmission sup-
plier. It is possible for the customer of the vehicle to equip the vehicle with systems
from different suppliers. A fleet manager maybe have different truck brands (e.g.
Navistar, Volvo and Freightliner) but wants to keep the same engine manufacturer
(e.g. Cummings) for the complete fleet and the same for the different systems, e.g.
transmission and brakes.
