PREVOST X3-45 Multiplex User Manual

Section 06: ELECTRICAL
PA1562
32
4.10 MULTIPLEX MODULES
4.10.1 CECM
The CECM plays the role of interface between
the engine ECM, the transmission ECU, the
telltale panel module and other IO-A, IO-B
modules. When a multiplex module is being
replaced, the CECM will inform the new module
of its role and function accordingly to the vehicle
options.
4.10.2 MASTER ID
The Master ID works in conjunction with the
CECM. It keeps the specific back-up program of
the vehicle. So, a specific Master ID cannot be
removed from a vehicle and installed on another
vehicle.
4.10.3 IO-A
IO-A modules receive inputs and control
outputs. IO-A's are used for all outputs of 1 amp
or less.
4.10.4 IO-B
IO-B modules receive inputs and control
outputs. IO-B's are used for outputs up to 30
amps.
4.11 MULTIPLEX MODULES REPLACEMENT
IO-A, IO-B and CECM multiplex modules can be
replaced and reprogrammed without having to
connect a computer to the vehicle.
Lower
screw
FIGURE 17: IO-B MODULE REMOVAL 06638
4.11.1 Replacing IO-A Or IO-B Modules
o Set the ignition key to the ON position and
leave it in that position at all time while
performing this procedure.
o Inside rear electrical compartment, trip circuit
breaker CB6.
o Replace the module (for IO-B modules,
disconnect the green connector first, then the
grey one and finish with the black connector.
To disconnect the black connector, slide
downwards the red latch. Remove the lower
screw that holds the cable attachment rod
onto the floor portion of the panel and flip the
rod up, this will relieve the IO-B module, (see
Fig. 17).
o Reset circuit breaker CB6. This engages the
automatic reprogramming.
o The telltale panel LCD display indicates
"CAN" until the reprogramming is complete.
Once completed, "CAN" disappears and the
temperature reappears.
o Check the SYSTEM DIAGNOSTIC menu of
the message center display (MCD). Select
FAULT DIAGNOSTIC and ELECTRICAL
SYSTEM. Verify the fault message to be
certain the module is reprogrammed. If the
module is not reprogrammed, the message
« Axx Not Responding » appears where Axx
is the module number (Ex: A41, A42…etc).
4.11.2 Replacing The CECM Module
o Set the ignition key to the ON position and
leave it in that position at all time while
performing this procedure.
o Inside rear electrical compartment, trip circuit
breaker CB6.
o Replace the module.
o Reset circuit breaker CB6. This engages the
program transfer from the Master ID to the
CECM module (the back-up program is
inside the Master ID. The Master ID will
identify the CECM as being new and will
send the correct program to it). The telltale
panel LCD display indicates "CAN" during 3
minutes approximately. "CAN" disappears
and "---" is displayed alternately with "CAN"
(during that sequence, "---" will be displayed
up to 6 times and the audible alarm will ring).
Wait until "CAN" is replaced by "---" that
remains for more than 10 seconds. At this
point the MasterID module has finished
loading the program in the CECM.
o Go to the rear electrical compartment and trip
circuit breaker CB6 once again. Wait 1
second and reset it. This engages I/O's
modules automatic reprogramming.
o The telltale panel LCD display indicates
"CAN" until the reprogramming is completed.
Once completed, "CAN" disappears and the
temperature reappears. Check the SYSTEM

PREVOST X3-45 Multiplex Specifications

General

Length	45 ft
Width	102 in
Engine	Volvo D13
Horsepower	500 hp
GVWR	54, 000 lbs
Height	146 in
Sleeping Capacity	Varies based on floor plan
Water Capacity	Varies based on floor plan