PREVOST LE MIRAGE XLII BUS SHELLS, Maintenance Manual

Page: 1236 / 1260

Section 26: XLII SLIDE-OUT
PA1564 24
FIGURE 36 : VEC CIRCUIT BREAKERS & FUSES
15.2.1 Multiplex fuses
The multiplex module outputs are protected in
current by an internal “soft-fuse”. Each output is
programmed to specific maximum amperage.
When an output is shorted, the current gets
above the limit and the soft-fuse intervenes to
turn the output OFF. The output stays OFF until
the "soft-fuse" is reset.
Turn the ignition key to the OFF position and
turn to the ON position again. This resets all
"soft-fuses".
CAUTION
Never put grease, Cortec VCI-238 or other
product on the multiplex modules connector
terminals.
15.3 PROBING VOLTAGE ON THE
MULTIPLEX CIRCUITS
Multiplex modules are supplied by 24 volts.
Inactive Multiplex output = Residual voltage of
18% to 33% of supply voltage.
Inactive Multiplex input = Residual voltage of
50% of supply voltage.
NOTE
For a 24V module: an active voltage would be
24V or 0V but not in between. If you measure
the intermediate tensions (ex. 12V, 4V, or 8V)
this must be interpreted as if the input or the
output is inactive.
15.4 MODULE REPLACEMENT
I/O-B and CECM multiplex modules can be
replaced and reprogrammed without having to
connect a computer to the vehicle.
15.4.1 I/O-B replacement
•
Turn the ignition key to OFF.
•
Replace the module (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).
•
Turn the ignition key to the ON position.
This engages the automatic
reprogramming,
•
The slide-out telltale light will turn on and
stay on until the reprogramming is
complete. Once completed, the slide-out
telltale light will turn off or stay on (not
blinking) if at least, one slide-out is
extended.
•
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 (A56 or A57).
15.4.2 CECM module replacement
•
Turn the ignition key to OFF.
•
Replace the module.
•
Turn the ignition key to the ON position.
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 slide-out telltale light
will turn on and stay on for a while, and
then will turn off. Wait until the slide-out
telltale starts blinking each second. At this
point, the MasterID module has finished
loading the program in the CECM.
•
Turn the ignition key to the OFF position
and then turn it back to the ON position.
This engages I/O's modules automatic
reprogramming.
•
The slide-out telltale light will turn on.
Once completed, the slide-out telltale light
will turn off or stay on (not blinking) if at
least, one slide-out is extended.