WORLDWIDE
ENGINEERING
STANDARDS
General Specification
Electrical Function
GMW3110
General Motors Local Area Network Enhanced Diagnostic Test Mode
Specification
© Copyright 2010 General Motors All Rights Reserved
February 2010
Originating Department: North American Engineering Standards
Page 1 of 336
1 Introduction.......................................................... 7
1.1 ....................................................................... 7
1.2 Mission/Theme. ............................................ 7
1.3 Classification.. .............................................. 7
2 References .......................................................... 7
2.1 External Standards/Specifications. ............... 7
2.2 GM Standards/Specifications. ...................... 8
2.3 Additional References. ................................. 8
2.3.1 GMLAN Specific Publications. ............... 8
2.3.2 Other Publications.................................. 9
3 Diagnostic Service Documentation Structure And
Convention ............................................................. 9
3.1 Request Message
Sub-Function Parameter
($Level) Definition. ............................................ 10
3.2
Request
Message
Data
Parameter
Definition. .......................................................... 10
3.3 Positive Response Message Data Parameter
Definition.. ......................................................... 10
3.4 (Test Mode) Service Identifier (SID)
Overview.. ......................................................... 10
3.5 Request and Positive Response Message
Table Structure.. ............................................... 11
3.6
Node Interface Function Symbol, Pseudo
Code, and Data Dictionary Definition. .............. 12
3.6.1 Symbol Definition.. ............................... 12
3.6.2 Pseudo Code Definition.. ..................... 13
3.6.3 Common/Global
Pseudo Code Data
Dictionary.. .................................................... 14
4 Diagnostic Strategy,
Service Overview, and
Implementation Rules and Requirements ............ 17
4.1 Diagnostic Message Strategy - USDT and
UUDT Messages. ............................................. 17
4.2 Diagnostic Service Table Overview. ........... 17
4.3 Diagnostic Communication
Implementation
Rules. ................................................................ 19
4.3.1 Tester Rules. ........................................ 19
4.3.2 Node (ECU) Rules. .............................. 21
4.3.3 Special
Considerations for Nodes
Operating as an On-board Test Device. ....... 21
4.3.4 Special Considerations for Nodes
Operating On Multiple GMLAN Subnets. ..... 21
4.4 Message Identification - Diagnostic CAN
Identifiers (CAN Identifiers). ............................. 22
4.4.1 Diagnostic CANId Definitions. ............. 22
4.4.2 CAN Identifier Memory Map Model. .... 23
4.4.3 CAN Identifier Table. ........................... 24
4.4.4 Rules For CAN Identifier Assignment.. 25
4.4.5 SPS Special
Case ECU Programming
CANId Assignments. .................................... 27
4.5 Message Addressing. ................................. 28
4.5.1 Frame Data Byte Definition Based On
Address Method. .......................................... 28
4.6 ECU Frame Padding Requirements. ......... 32
4.7 Communication Layer Interaction. ............. 32
4.7.1
GMLAN
Communication
Layer
Interaction. .................................................... 33
4.8 Network Layer Buffer Requirements. ......... 34
4.8.1
Buffer
Requirements
for
Normal
Operation and Diagnostics. .......................... 34
4.8.2 Buffer
Requirements During SPS
Programming. ............................................... 35
4.9 Diagnostic Message Sequence Examples. 35
4.9.1
General
USDT
and
UUDT
Request/Response Sequence Examples. .... 35
4.9.2 Interleaving Single Frame and Multi-
Frame Diagnostic Messages. ....................... 37
4.10 Functional System Assignments. ............. 38
4.10.1 Definition of a Functional System. ..... 38
4.10.2 Functional System Table.. ................. 39
5 Diagnostics and Node Management................. 39
5.1 Interaction between
Diagnostics and Node
Management. ................................................... 39
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