Description

DiagNation Network Nightmares Series Network Protocols Waveforms Reference

Authors: Adam Robertson and Gary Smith

Communication network diagnostics are by far one of the toughest diagnostic challenges in the automotive service industry today. Manufacturers have deployed an ever-changing variety of standardized (and proprietary) network protocols to communicate between modules and via gateways between multiple networks. These systems have morphed into multi-layered control, transport and PHY configurations running on complex topologies, with Transport Layer packets that now handle multiple protocols data transport simultaneously.

In modern vehicles, because modules share critical data between domain controllers, diagnosing, debugging and tracking down intermittent network faults in any automotive or truck platform can be exceedingly challenging, whether at end of line in production or once out in the field with unpredictable environmental and physical impacts in play.

Table of Contents:
Introduction and Author’s Notes (Page 1)
Diagnostic Tips to Consider (Page 4)
The Network Protocols (Page 9)
Automotive Ethernet (Page 10)
MOST Bus (Wired MOST150) (Page 19)
FlexRay Protocol (Page 24)
High-Speed CAN-C and CAN-FD (Page 28)
Medium & Low-Speed CAN (Page 35)
Low –Speed and Single Wire CAN (Page 45)
Ford J-1850 PWM Ford SCP (Page 50)
SENT: Single Edge Nibble Transmit (Page 54)
Early UART (Universal Asynchronous Receive-Transmit) (Page 58)
GM Class 2 and Chrysler PCI (Page 60)
Ford UBP (UART-Based Protocol) (Page 63)
LIN Bus (Local Interconnect Network) (Page 66)
K-Line and L-Line Protocol (Page 71)
Honda KWP-2000 and Slow-Init (Page 76)
Chrysler SCI and CCD (Chrysler Collision Detection) (Page 79)
Addendums:
Network Testing Techniques (Page 91)
Probe Loading and Calibration Considerations (Page 96)
Equipment Fault Considerations and Cautions (Page 101)
Math Channels and Serial Decoding Examples (Page 105)
Wakeup, Sleep and Bias Discussion (Page 112)