The glow plug system is
electronically controlled by the PCM
and GPCM. The GPCM energizes the
glow plugs immediately after the
ignition is turned on and kept on as determined by the GPCM using the
ECT, BARO and environmental temperature sensor. The required time
for the glow plugs to be energized decreases as the coolant temperature,
barometric pressure and environmental temperature increase.
Engine and secondary cooling system
The cooling system contains an engine cooling loop to cool the engine
and a secondary cooling loop to cool the transmission, exhaust gas
recirculation (EGR), charge air and fuel. The coolant serves three
primary purposes: to provide heat transfer, freeze point protection, and
corrosion protection using additives.
Vehicles with diesel engines typically are used to carry heavy loads and
accumulate mileage rapidly. These two factors may cause the additives in
the coolant to “wear out” in a shorter time. Refer to theSpecial
operating conditionssection for more information about coolant
additives and coolant change intervals. Operating the engine with
insufficient coolant and/or coolant additive can cause severe engine
damage.
Selective catalytic reduction (SCR) system
Your vehicle is equipped with a selective catalytic reduction (SCR)
system to help reduce emission levels of oxides of nitrogen from the
exhaust of the diesel engine. This system relies on the use of diesel
exhaust fluid (DEF) which must be replenished at certain intervals.
Failure to maintain proper DEF levels or if the DEF becomes
contaminated will result in vehicle speed limitations and/or result in the
vehicle entering an idle-only mode. SeeSelective catalytic reduction
(SCR) systemin theMaintenance and Specificationschapter for more
information.
Speed control (if equipped)
If vehicle speed goes outside a predetermined range from the set speed,
the RES (Resume) function will not reset vehicle speed. Vehicle speed
will need to be reset with the SET +/- button after reaching desired
speed using accelerator pedal.
Introduction
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eliminated, but the exhaust system and exhaust gas may still be hot. If
the vehicle is shut off during OCR, you will notice turbo flutter. This is a
normal consequence caused by shutting off a diesel engine during
boosted operation and is considered normal.
Filter service/maintenance
Over time a slight amount of ash will build up in the DPF which is not
removed during the regeneration process. The DPF may need to be
removed for ash cleaning at approximately 120,000 miles (193,000 km)
or greater (actual mileage can vary greatly depending upon
engine/vehicle operating conditions) and replaced with a new or
remanufactured (ash cleaned) part. The filter may need to be replaced
at approximately 250,000 miles (400,000 km) depending upon
engine/vehicle operating conditions. In both cases the engine control
system will set a service light
to inform you to bring the vehicle to
the dealer for service.
If there are any issues with the oxidation catalyst/DPF system a service
light
orwill be set by the engine control system to inform
you to bring the vehicle into your authorized dealer for service.
Resonator/Tailpipe assembly maintenance
The diesel resonator tail-pipe assembly is a uniquely functioning device
that accompanies the Oxidation Catalyst/DPF assembly. The assembly
serves multiple functions. First it serves as an acoustic device to
attenuate exhaust noise. Second it provides an exit path for the exhaust
from the vehicle. It also is designed to help control the temperature of
the exhaust during DPF regeneration events. The visible holes in each
leg of the twin tip and the holes under the shield just inboard of the
right rear tire(s) are functional. The holes need to be kept clear of
mud/debris or foreign material to maintain proper function of the
exhaust system. Clean and remove debris or foreign material if present
as needed. Spraying with a hose during regular washing of vehicle should
help keep holes clean and clear of debris or foreign material.
Note:Additions of aftermarket devices or modifications to the exhaust
system can reduce the effectiveness of the exhaust system as well as
cause damage to the exhaust system and/or engine. These actions may
also affect the vehicle’s warranty. See theWarranty Guidefor more
information.
Maintenance and Specifications
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