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2.4 J1939 Standards Collection

The J1939 specification is described by a number of SAE documents, the SAE J1939 Standards Collection:

Document 

Description

J1939

Recommended Practice for a Serial Control and Communications Vehicle Network*

J1939-01

Recommended Practice for Control And Communications Network for On-Highway Equipment
J1939-02 Agricultural and Forestry Off-Road Machinery Control and Communication Network**

J1939-11

Physical Layer - 250k bits/s, Twisted Shielded Pair

J1939-13

Off-Board Diagnostics Connector

J1939-15

Reduced Physical Layer, 250k bits/sec, Un-Shielded Twisted Pair (UTP)

J1939-21

Data Link Layer

J1939-31

Network Layer

J1939-71

Vehicle Application Layer

J1939-73

Application Layer - Diagnostics

J1939-74

Application - Configurable Messaging

J1939-75

Application Layer - Generator Sets and Industrial

J1939-81

Network Management

* This document seems to be obsolete. The hyperlink on the SAE web site produces an error message.


** This document is not listed in the "Core J1939 Standards" list on the SAE web site, but it can be found through their search feature.
Reference: http://www.sae.org/technical/standards/J1939/2_200608


The SAE has named further documents addressing the transport, session, and presentation layer in the ISO/OSI 7-Layer Reference Model. These layers are not documented (in all consequence they are not necessary for J1939) and thus the corresponding documents have not been created.

While researching the Internet (Google Search) further documents are mentioned on various web sites. They are, however, not available through the SAE. A search on their web site did not produce any results.

J1939-12

Physical Layer - Twisted Quad of Wires

J1939-14

DIN 9684 - 50k bits/sec*

J1939-72

Virtual Terminal (DIN 9684)*

* Source: CAN-in-Automation (CiA). DIN is a German standardization system and the connection to the SAE J1939 standard is not clear at this time.

 

J1939-11 Physical Layer

The physical layer of J1939 is based on Controller Area Network (CAN) as described in ISO11898. J1939-11 specifies a shielded twisted pair wire with a maximum length of 40 m (roughly 120 ft.). The CAN baud rate is 250 Kbit/sec per standard. The maximum number of ECUs is limited to 30 for one segment. Several units may be connected using special interconnection ECUs.

J1939-13 Off-Board Diagnostic Connector

J1939-13 defines a standard connector for diagnostic purpose. The connector is a Deutsch HD10 - 9 – 1939 (9 pins, round connector).
 

J1939/15 Reduced Physical Layer

J1939/15 describes a physical layer that utilizes an Unshielded Twisted Pair (UTP) cable.

J1939-21 Data Link Layer

J1939-21 defines the use of the CAN data frame (29-bit identifier, Permanent Group Numbers - PGN etc.) and the transport protocol functions, i.e. a definition of how messages longer than the standard CAN data length (8 bytes) are transmitted in a J1939 bus network. 

J1939-31 Network Layer

J1939-31 describes the services and functions needed for intercommunication between different segments of a J1939 network.

J1939-71 Vehicle Application Layer

J1939-71 describes and defines the Permanent Group Numbers. This document is updated very frequently to incorporate new standard parameters and messages.   

J1939-73 Application Layer – Diagnostics

J1939-71 defines functions and messages for accessing diagnostic and calibration data. There are several predefined Diagnostic Messages (DM) used for:

  • Reading and writing to ECU memory

  • Reporting diagnostic information when running

  • Identification of lamp status

  • Reading and clearing Diagnostic Trouble Codes (DTCs)

  • Start/stop broadcast DMs

J1939/74 Application - Configurable Messaging

J1939/74 describes the message structure for a set of messages that enable the user to determine and announce the parameter placement within a particular message.

J1939/75 Application Layer - Generator Sets and Industrial

J1939/75 describes the parameters and parameter groups predominantly associated with monitoring and control generators and other driven equipment for electric power generation as well as industrial applications.

J1939-81 Network Management

J1939-81 provides information about the architecture of an ECU Name and how the ECU claims an addressing using that Name. The Name is a 64 bit (8 bytes) long number giving every ECU a unique identity.