PREVOST X3-45 COMMUTER, Maintenance Manual

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SECTION 06: ELECTRICAL
36 DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version) – Sec 06 revised June 2017
charger is connected and then restart the
vehicle.
4.11.1 Available Functions

Startup: turn on the ignition in the
driver's area and rear start the vehicle
from the engine compartment,

Opening the door: functions normally,

Closing the door: manually pull on the
door panels and it will lock
automatically,

Windshield wipers: wipers functions at
1st speed only,

Headlights: low beams only,

Directional signals: rear and front only,

Stoplights: 2 upper stop high-
mounted stoplight are functional,

HVAC: functional with set point fixed at
68°f (20°c), evaporator and condenser
fixed at speed 1, defroster fixed at
speed 4.
4.12 LOWER PRIORITY MODULES FOR
BREAKDOWN SERVICE
Modules A43 (I/O-A) and A44 (I/O-B) affect
lower priority functions. These modules can
therefore be used as spare parts for breakdown
service while on the road.
Functions lost if A43 is removed and used as
spare part:

High beams,

Ability to turn on the parking lights only,

“watch your step” sign,

Driver ceiling light,

Tag axle activation,

Courtesy flashers
Functions lost if A44 is removed and used as
spare part:

Fresh air damper mix trap control,

Driver's area and entrance ceiling lights,

Front clearance lights.
4.13 MULTIPLEX MODULES
4.13.1 MCM Module
The mcm plays the role of interface between the
engine ECM, the transmission TCM, the telltale
panel module and other IO-A, IO-B modules.
When a multiplex module is being replaced, the
mcm will inform the new module of its role and
function accordingly to the vehicle options. The
mcm keeps the back-up of the vehicle specific
multiplex program.
4.13.2 IO-A Module
Io-a modules receive inputs and control outputs.
Io-a's are used for all outputs of 1 amp or less.
4.13.3 IO-B Module
Io-b modules receive inputs and control outputs.
Io-b's are used for outputs up to 30 amps.
4.14 MULTIPLEX MODULES REPLACEMENT
IO-A, IO-B multiplex modules can be replaced
and reprogrammed without having to connect a
computer to the vehicle.
The mcm must be reprogrammed using a laptop
computer equipped with VPG software,
connected to c226 (db9 connector) found in the
front electrical compartment (see Figure 29).
However, an updated vehicle multiplex program
saved on a laptop computer can be uploaded
into the mcm without the need of vpg software.
Lower screw
FIGURE 28: IO-B MODULE REMOVAL 06638
4.14.1 Replacing IO-A or IO-B Modules
Set the ignition switch to the on position and
leave in that position at all time while performing
this procedure.
1. On rear electrical junction panel, trip circuit
breaker cb6.
2. Replace the module and plug connectors
(for
IO-B modules, disconnect the green