2009 GMC YUKON engine overheat

Retained Accessory Power (RAP)
The following vehicle accessories can be used for up to
10 minutes after the engine is turned off:
Audio System
Power Windows
OnStar®System (if equipped)
Sunroof (if equipped)
These features work when the key is in ON/RUN or
ACC/ACCESSORY. Once the key is turned from
ON/RUN to LOCK/OFF, the windows and sunroof
continue to work up to 10 minutes until any door
is opened. The radio continues to work for up to
10 minutes or until the driver door is opened.
Starting the Engine
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Move the shift lever to P (Park) or N (Neutral). The
engine will not start in any other position. To restart the
engine when the vehicle is are already moving, use
N (Neutral) only.
Notice:Do not try to shift to P (Park) if the vehicle
is moving. If you do, you could damage the
transmission. Shift to P (Park) only when the vehicle
is stopped.
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 the 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.
The 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.
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Engine Coolant Heater
The engine coolant heater can provide easier starting
and better fuel economy during engine warm-up in cold
weather conditions at or below 0°F (−18°C). Vehicles
with an engine heater should be plugged in at least
four hours before starting. An internal thermostat in
the plug-end of the cord may exist which will prevent
engine coolant heater operation at temperatures above
0°F (−18°C).
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver’s side of the engine
compartment, near the power steering uid
reservoir.
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.
The length of time the heater should remain plugged in
depends on several factors. Ask a dealer/retailer in
the area where you will be parking the vehicle for the
best advice on this.
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Shifting Into Park
{CAUTION:
It can be dangerous to get out of the vehicle if the
shift lever is not fully in P (Park) with the parking
brake rmly set. The vehicle can roll. If you have left
the engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, use the steps that follow. With
four-wheel drive, if the transfer case is in Neutral,
the vehicle will be free to roll, even if the shift lever
is in P (Park). So, be sure the transfer case is in a
drive gear — not in Neutral. If you are pulling a
trailer, seeTowing a Trailer on page 4-52.
1. Hold the brake pedal down, then set the parking
brake.
SeeParking Brake on page 2-42for more
information.
2. Move the shift lever into the P (Park) position by
pulling the shift lever toward you and moving it up
as far as it will go.3. Be sure the transfer case is in a drive gear — not
in N (Neutral).
4. Turn the ignition key to LOCK/OFF.
5. Remove the key and take it with you. If you can
leave the vehicle with the ignition key in your
hand, the vehicle is in P (Park).
Leaving the Vehicle With the Engine
Running
{CAUTION:
It can be dangerous to leave the vehicle with the
engine running. The vehicle could move suddenly
if the shift lever is not fully in P (Park) with the
parking brake rmly set.
If you have four-wheel drive and the transfer case
is in Neutral, the vehicle will be free to roll, even if
the shift lever is in P (Park). So be sure the
transfer case is in a drive gear — not in Neutral.
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 the vehicle
with the engine running unless you have to.
2-44

Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard the vehicle is
working. During a majority of the operation, the gage
reads 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 5-35.
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Tire Pressure Light
For vehicles with a tire
pressure light, this light
comes on briey when
the engine is started and
provides information about
tire pressures and the Tire
Pressure Monitoring
System.
When the Light is On Steady
This indicates that one or more of the tires is signicantly
underinated.
A tire pressure message in the Driver Information
Center (DIC), can accompany the light. SeeDIC
Warnings and Messages on page 3-64for more
information. Stop and check the tires as soon as it is
safe to do so. If a tire is underinated, inate to the
proper pressure. SeeTires on page 5-62for more
information. United StatesCanada
3-43

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 5-35
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 3-43.
SeeOverheated Engine Protection Operating Mode on
page 5-37for information on driving to a safe place
in an emergency.
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 5-35
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 5-35for 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 3-50andFuel on page 5-5for more
information.
HEATED WASHER FLUID SYSTEM OFF
This message displays when the heated windshield
washer has been turned off. SeeWindshield Washer on
page 3-10for more information.
3-66

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 3-40.
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 also displays if the vehicle is shifted
into 4LO.
The message turns off as soon as the conditions that
caused the message to be displayed are no longer
present.
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 3-44. Reinstall the fuel cap fully.
SeeFilling the Tank on page 5-9. 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
On vehicles with the Tire Pressure Monitor System
(TPMS), this message displays when the 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. SeeTire Inspection
and Rotation on page 5-78,Tire Pressure Monitor
System on page 5-72, andInflation - Tire Pressure on
page 5-70for more information.
3-72

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.
TRAILER CONNECTED
On vehicles with the Integrated Trailer Brake Control
(ITBC) system, this message displays briey when
a trailer with electric brakes is rst connected to
the vehicle.
This message clears itself after several seconds. This
message also clears if you acknowledge it. After
this message clears, the TRAILER GAIN/OUTPUT
display appears in the DIC.
See “TRAILER GAIN/OUTPUT” underDIC Operation
and Displays (With DIC Buttons) on page 3-52orDIC
Operation and Displays (Without DIC Buttons) on
page 3-57and “Integrated Trailer Brake Control System”
underTowing a Trailer on page 4-52for 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 sound 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.
3-73

Driving Downhill
When off-roading takes you downhill, consider:
How steep is the downhill? Will I be able to maintain
vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What is at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, try to keep
the vehicle headed straight down. Use a low gear
so engine drag can help the brakes so they do not have
to do all the work. Descend slowly, keeping the
vehicle under control at all times.
{CAUTION:
Heavy braking when going down a hill can cause
your brakes to overheat and fade. This could cause
loss of control and a serious accident. Apply the
brakes lightly when descending a hill and use a low
gear to keep vehicle speed under control.Things not to do when driving down a hill:
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down might be too steep to drive
across. The vehicle could roll over.
Never go downhill with the transmission in
N (Neutral), called free-wheeling. The brakes will
have to do all the work and could overheat
and fade.
Vehicles are much more likely to stall when going uphill,
but if it happens when going downhill:
1. Stop the vehicle by applying the regular brakes and
apply the parking brake.
2. Shift to P (Park) and, while still braking, restart the
engine.
3. Shift back to a low gear, release the parking brake,
and drive straight down.
4. If the engine will not start, get out and get help.
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