2008 GMC YUKON DENALI engine overheat

Starting Procedure
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts,
let go of the key. The idle speed will go down as
your engine gets warm. Do not race the engine
immediately after starting it. Operate the engine and
transmission gently to allow the oil to warm up
and lubricate all moving parts.
Your vehicle has a Computer-Controlled Cranking
System. This feature assists in starting the
engine and protects components. If the ignition key
is turned to the START position, and then
released when the engine begins cranking, the
engine will continue cranking for a few seconds or
until the vehicle starts. If the engine does not
start and the key is held in START for many
seconds, cranking will be stopped after 15 seconds
to prevent cranking motor damage. To prevent
gear damage, this system also prevents cranking if
the engine is already running. Engine cranking
can be stopped by turning the ignition switch to the
ACC/ACCESSORY or LOCK/OFF position.
Notice:Cranking the engine for long periods of
time, by returning the key to the START position
immediately after cranking has ended, can overheat
and damage the cranking motor, and drain the
battery. Wait at least 15 seconds between each try,
to let the cranking motor cool down.2. If the engine does not start after 5-10 seconds,
especially in very cold weather (below 0°F or−18°C),
it could be ooded with too much gasoline. Try
pushing the accelerator pedal all the way to the oor
and holding it there as you hold the key in START for
up to a maximum of 15 seconds. Wait at least
15 seconds between each try, to allow the cranking
motor to cool down. When the engine starts, let go of
the key and accelerator. If the vehicle starts briey
but then stops again, do the same thing. This clears
the extra gasoline from the engine. Do not race the
engine immediately after starting it. Operate the
engine and transmission gently until the oil warms up
and lubricates all moving parts.
Notice:The engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer/retailer. If you do not, your
engine might not perform properly. Any resulting
damage would not be covered by your vehicle’s
warranty.
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3. Plug the cord into a normal, grounded 110-volt
AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a re. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord will
not reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you do not, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer/retailer in the area where you will be
parking your vehicle. The dealer/retailer can give you
the best advice for that particular area.
Automatic Transmission Operation
Your vehicle has a Hydra-Matic®6L80 automatic
transmission, and has an electronic shift position
indicator within the instrument panel cluster. The
electronic shift position indicator displays when the shift
lever is moved out of PARK (P).
There are several different positions for the shift lever.
See “Range Selection Mode” later in this section.
PARK (P):This position locks your rear wheels. It is
the best position to use when you start your engine
because your vehicle cannot move easily.
When parked on a hill, especially when the vehicle has
a heavy load, you may notice an increase in the
effort to shift out of Park. See Torque Lock (Automatic
Transmission) underShifting Into PARK (P) on
page 2-36for more information.
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Shifting Into PARK (P)
{CAUTION:
It can be dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P) with
the parking brake rmly set. Your vehicle can
roll. If you have left the engine running, the
vehicle can move suddenly. You or others
could be injured. To be sure your vehicle will
not move, even when you are on fairly level
ground, use the steps that follow. If you are
pulling a trailer, seeTowing a Trailer on
page 4-42.
1. Hold the brake pedal down with your right foot and
set the parking brake.
2. Move the shift lever into the PARK (P) position by
pulling the shift lever toward you and moving it up
as far as it will go.
3. Turn the ignition key to LOCK/OFF.
4. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
Leaving Your Vehicle With the Engine
Running
{CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in
PARK (P) with the parking brake rmly set.
And, if you leave the vehicle with the engine
running, it could overheat and even catch re.
You or others could be injured. Do not leave
your vehicle with the engine running.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P) and the
parking brake is rmly set. After the shift lever is moved
into PARK (P), hold the regular brake pedal down.
Then, see if you can move the shift lever away from
PARK (P) without rst pulling it toward you. If you can, it
means that the shift lever was not fully locked into
PARK (P).
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Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210°F (100°C) or less. If you are pulling a load
or going up hills, it is normal for the temperature to
uctuate and approach the 250°F (122°C) mark. If the
gage reaches the 260°F (125°C) mark, it indicates
that the cooling system is working beyond its capacity.
SeeEngine Overheating on page 5-26.
Tire Pressure Light
This light comes on briey
when the engine is started.
This light will also come on when one or more of your
tires are signicantly underinated.
A tire pressure message in the Driver Information
Center (DIC), may accompany the light. SeeDIC
Warnings and Messages on page 3-56for more
information.
Stop and check your tires as soon as it is safe to do so.
If underinated, inate to the proper pressure. See
Tires on page 5-55for more information.
If a problem is detected with the Tire Pressure Monitor
System, this light will ash for approximately
60 seconds and then stay on solid for the remainder of
the ignition cycle. SeeTire Pressure Monitor System
on page 5-62for more information. United States
Canada
3-41

DRIVER DOOR OPEN
This message displays and a chime sounds if the driver
door is not fully closed and the vehicle is in a drive
gear. Stop and turn off the vehicle, check the door for
obstructions, and close the door again. Check to
see if the message still appears on the DIC.
ENGINE HOT A/C (Air Conditioning)
TURNED OFF
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
SeeEngine Coolant Temperature Gage on page 3-41.
To avoid added strain on a hot engine, the air
conditioning compressor automatically turns off. When
the coolant temperature returns to normal, the air
conditioning compressor turns back on. You can
continue to drive your vehicle.
If this message continues to appear, have the system
repaired by your dealer/retailer as soon as possible
to avoid damage to the engine.
ENGINE OVERHEATED IDLE ENGINE
Notice:If you drive your vehicle while the engine is
overheating, severe engine damage may occur. If
an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon
as possible. SeeEngine Overheating on page 5-26
for more information.
This message displays when the engine coolant
temperature is too hot. Stop and allow the vehicle to
idle until it cools down. SeeEngine Coolant
Temperature Gage on page 3-41.
SeeOverheated Engine Protection Operating Mode on
page 5-28for information on driving to a safe place
in an emergency.
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ENGINE OVERHEATED STOP ENGINE
Notice:If you drive your vehicle while the engine
is overheating, severe engine damage may occur.
If an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon as
possible. SeeEngine Overheating on page 5-26
for more information.
This message displays and a chime sounds if the
engine cooling system reaches unsafe temperatures for
operation. Stop and turn off the vehicle as soon as it
is safe to do so to avoid severe damage. This message
clears when the engine has cooled to a safe operating
temperature.
ENGINE POWER IS REDUCED
This message displays and a chime sounds when the
cooling system temperature gets too hot and the engine
further enters the engine coolant protection mode.
SeeEngine Overheating on page 5-26for further
information.
This message also displays when the vehicle’s engine
power is reduced. Reduced engine power can affect the
vehicle’s ability to accelerate. If this message is on,
but there is no reduction in performance, proceed
to your destination. The performance may be reduced
the next time the vehicle is driven.The vehicle may be driven at a reduced speed while
this message is on, but acceleration and speed may be
reduced. Anytime this message stays on, the vehicle
should be taken to your dealer/retailer for service
as soon as possible.
FUEL LEVEL LOW
This message displays and a chime sounds if the fuel
level is low. Refuel as soon as possible. SeeFuel Gage
on page 3-48andFuel on page 5-5for more
information.
HOOD OPEN
This message displays and a chime sounds if the hood is
not fully closed. Stop and turn off the vehicle, check the
hood for obstructions, and close the hood again. Check to
see if the message still appears on the DIC.
LEFT REAR DOOR OPEN
This message displays and a chime sounds if the driver
side rear door is not fully closed and the vehicle is in
a drive gear. Stop and turn off the vehicle, check
the door for obstructions, and close the door again.
Check to see if the message still appears on the DIC.
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SERVICE TRACTION CONTROL
If your vehicle has StabiliTrak®, this message displays
when there is a problem with the Traction Control
System (TCS). When this message displays, the system
will not limit wheel spin. Adjust your driving accordingly.
See your dealer/retailer for service. SeeStabiliTrak
®
System on page 4-6for more information.
STABILITRAK OFF
If your vehicle has StabiliTrak®, this message displays
when you turn off StabiliTrak®, or when the stability
control has been automatically disabled. To limit wheel
spin and realize the full benets of the stability
enhancement system, you should normally leave
StabiliTrak
®on. However, you should turn StabiliTrak®
off if your vehicle gets stuck in sand, mud, ice, or
snow and you want to rock your vehicle to attempt to
free it, or if you are driving in extreme off-road conditions
and require more wheel spin. SeeIf Your Vehicle is
Stuck in Sand, Mud, Ice, or Snow on page 4-32. To turn
the StabiliTrak
®system on or off, seeStabiliTrak®
System on page 4-6.There are several conditions that can cause this
message to appear.
One condition is overheating, which could occur if
StabiliTrak®activates continuously for an extended
period of time.
The message also displays if the brake system
warning light is on. SeeBrake System Warning
Light on page 3-39.
The message could display if the stability system
takes longer than usual to complete its diagnostic
checks due to driving conditions.
The message displays if an engine or vehicle
related problem has been detected and the vehicle
needs service. See your dealer/retailer.
The message turns off as soon as the conditions that
caused the message to be displayed are no longer
present.
3-62

TIGHTEN GAS CAP
This message may display along with the check engine
light on the instrument panel cluster if the vehicle’s
fuel cap is not tightened properly. SeeMalfunction
Indicator Lamp on page 3-42. Reinstall the fuel cap fully.
SeeFilling the Tank on page 5-7. The diagnostic
system can determine if the fuel cap has been left off or
improperly installed. A loose or missing fuel cap
allows fuel to evaporate into the atmosphere. A few
driving trips with the cap properly installed should turn
this light and message off.
TIRE LEARNING ACTIVE
This message displays when the Tire Pressure Monitor
System (TPMS) is re-learning the tire positions on your
vehicle. The tire positions must be re-learned after
rotating the tires or after replacing a tire or sensor. See
Tire Inspection and Rotation on page 5-67,Tire Pressure
Monitor System on page 5-62, andInflation - Tire
Pressure on page 5-60for more information.
TRACTION CONTROL OFF
If your vehicle has StabiliTrak®, this message displays
when the Traction Control System (TCS) is turned
off. Adjust your driving accordingly. SeeStabiliTrak
®
System on page 4-6for more information.
TRANSMISSION HOT IDLE ENGINE
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed on
the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by
your warranty. Do not drive your vehicle with
overheated transmission uid or while the
transmission temperature warning is displayed.
This message displays along with a continuous chime if
the transmission uid in the vehicle gets hot. Driving
with the transmission uid temperature high can cause
damage to the vehicle. Stop the vehicle and let it
idle to allow the transmission to cool. This message
clears and the chime stops when the uid temperature
reaches a safe level.
TURN SIGNAL ON
This message displays and a chime sounds if a turn
signal is left on for 3/4 of a mile (1.2 km). Move the turn
signal/multifunction lever to the off position.
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