Page 4 of 72
The FCM/HFCM should be drained
at regular intervals or when the
WATER IN FUEL light illuminates in
the instrument cluster.
The fuel injectors are located in the center of the combustion chambers
in the cylinder head between the rocker arm assemblies. The glow plug
system and fuel injection system are controlled through the Powertrain
Control Module (PCM) and Fuel Injection Control Module (FICM).
Fuel is drawn from the fuel tank by a frame-mounted electric fuel pump.
The fuel pump provides pressurized fuel to the engine and is
electronically controlled by the fuel pump PCM relay. The fuel pump
contains a pressure relief valve for overpressure protection in the event
of restricted flow.
Lubrication system
It is important to change the engine oil at the recommended service
intervals, because oil viscosity is important in maintaining the oil
pressure required to actuate the fuel injectors. Extended oil change
intervals can negatively affect engine performance, fuel economy and
engine life. Refer to the engine oil specification chart located under
Engine oil specificationsin theMaintenance and Specifcations
section of this supplement.
Fast start glow plug system
The glow plug system consists of:
•eight glow plugs
•the glow plug control module (GPCM)
•engine oil temperature (EOT) sensor
•barometric pressure (BARO) sensor
The glow plug system is
electronically controlled by the
PCM. The GPCM energizes the glow
plugs immediately after the ignition
is placed in the ON position, then determines how long the glow plugs
will be on according to the EOT and BARO sensors. The required time
for the glow plugs to be energized decreases as the engine oil
temperature and barometric pressure increase.
Introduction
4
Page 9 of 72
The vehicle may be driven with the engine air filter warning light
illuminated/or when the underhood air filter restriction gauge has moved
to the CHANGE FILTER mark for up to 400 km (250 miles) without
damaging the engine or related components. However, the air filter
element must be replaced at the earliest opportunity. Refer toAir filter
restriction gauge (if equipped)in this section of the supplement for
more information.
Transmission Tow/Haul Feature
(if equipped):Illuminates when
the Tow/Haul feature has been
selected. Refer to theDriving
chapter for transmission function and operation. If the light flashes
steadily or does not illuminate, have the transmission serviced soon, or
damage may occur.
Air filter restriction gauge (if equipped)
The restriction gauge, located on
the upper housing of the air cleaner
assembly, monitors the condition of
the air filter element in two ways:
•First, the colored indictor inside
the gauge highlights the
percentage that the air filter
element is clogged with dust or
contaminants. Refer to
Maintenance and Specifications
section of this supplement.
•Second, the gauge contains an
electrical switch which illuminates
a warning light on the instrument
cluster when the air filter element
is 100% clogged. Refer to the
Engine air filterwarning light in
this section of the supplement.
Check the air filter restriction gauge
whenever the hood is raised to
perform general engine maintenance at least every 7,500 miles (12,000
km). If the vehicle is operated in extremely dusty conditions, check the
gauge at least every 500 miles (800 km), or two weeks, whichever comes
first.
AIRFILTERRESTAA
CHANGE FILTER
PUSH BUTTON RESET75%
50%65%
Instrumentation
9
Page 10 of 72
The air filter element must be
replaced when the colored band on
the gauge reaches the CHANGE
FILTER mark. Engine performance
and fuel economy are adversely
affected when the maximum
restriction is reached.
Blowing-out the air filter
element with compressed air is
not recommended as the
compressed air may damage the
filter paper.
Note:It is not possible to determine
the level of filter clogging by visual
appearance alone. A filter which
appears to be dirty may actually
have several thousand miles
(kilometers) of life remaining.
Always use the underhood air
filter restriction gauge to
determine when the air filter element needs to be changed. The
warning light on the instrument cluster should not be used
exclusively for determining when the air filter element needs
changing.
AIRFILTERRESTAA
CHANGE FILTER
PUSH BUTTON RESET75%
50%65%
Instrumentation
10
Page 11 of 72
After servicing the air filter element,
reset the restriction gauge by
pressing the button on the end of
the gauge.
Note:If the vehicle is operated in a
heavy snow storm, in blowing snow
or the vehicle is equipped with a
snowplow, the engine air filter
element may become partially
clogged with snow and/or ice. If this
occurs, the air filter restriction
gauge will move to the CHANGE FILTER mark and the engine may
experience a significant reduction in power output. The vehicle may be
driven under these conditions for up to 160 km (100 miles) without
damage to the engine or related components.
At the earliest opportunity, clear all snow and ice from the air induction
system and reset the restriction gauge by pressing the button on the end
of the gauge. If the air filter restriction gauge moves the CHANGE
FILTER mark after clearing snow and/or ice, then replace the filter.
Reset filter restriction gauge after changing the air filter element.
The air filter warning light on the instrument cluster may be used, in
addition to the underhood restriction gauge, to monitor the condition of
the air filter element. Refer to theEngine air filterwarning light in this
section of the supplement.
Engine boost gauge (if equipped)
Indicates the amount of pressure in
the engine. Driving with your
pointer continuously at the high end
of the scale may damage the engine.
Instrumentation
11
