Paccar Kenworth T680 2019 Manual page 151

INTRODUCTION
This section is written to provide information to the body builder when installing equipment into vehicles built with Multi-
plexed instrumentation. The new technology presented by VECU level instrumentation integrates J-1939 CAN data com-
munications between equipment on the vehicle. This book is intended to address how to work in aftermarket equipment
while still maintaining full functionality of the OEM vehicle.
These topics apply to 2.1M chassis built with VECU architecture. The electrical architecture for these trucks will be named
VECU01 which replaces NAMUX4.This system integrates a parallel control unit to manage outbound messages via a
faster baud rate 500kbps and FCAN signals for the chassis module(s). All other CAN busses (except the K-CAN) are
managed in parallel with the existing CECU3 unit. Since the F-CAN has moved to the VECU, the VCAN on CECU3 is now
divided into a 1 (250 kbps) and 2 (500 kbps). The second CAN is dedicated to OBD communication.
The most important advancement of electrical instrumentation is the implementation of the VECU controller. While it is still
possible to wire completely outside of the VECU system, utilizing the VECU functions will make a cleaner installation and
will maintain OEM functionality. VECU expands controls to air operated devices by receiving input from dash switches, re-
mote (aftermarket) switches, sensors mounted to the aftermarket equipment and other vehicle parameters (engine speed,
transmission status etc.) With the proper programming, the VECU will then process the inputs and will create a J-1939
Data instruction which is communicated to another controller outside the cab called the Chassis Module. This chassis
module receives the instruction and connects 12V power to an air solenoid. 12V power will open the solenoid and supply
air pressure to that air circuit.
ELECTRICAL ACRONYM LIBRARY
Acronym Definition
CAN Controller Area Network
CECU Cab Electrical Control Unit
DTC Diagnostics Trouble Code
ECM Engine Control Module
ECU Electrical Control Unit
EOA Electric Over Air
EOH Electric Over Hydraulic
J-1939 SAE CAN Communication Standard
LIN Local Interconnect Network
MSB Master Solenoid Bank
MSM Master Switch Module
MUX Multiplex Switch
OBD On Board Diagnostics
OEM Original Equipment Manufacture
PCC Predictive Cruise Control
PDC Power Distribution Center
PGN Parameter Group Number
PTO Power Take Off
RP1226 TMS Messaging Standard
SPN Suspect Parameter Number
TCM Transmission Control Module
VECU Vehicle Electrical Control Unit
10-1
Section 9
Electrical
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