2006 GMC YUKON Engine

Engine Coolant Heater
Your vehicle may be equipped with an engine
coolant heater.
In very cold weather, 0°F (−18°C) or colder, the engine
coolant heater can help. You will get easier starting
and better fuel economy during engine warm-up.
Usually, the coolant heater should be plugged in a
minimum of four hours prior to starting your vehicle.
At temperatures above 32°F (0°C), use of the coolant
heater is not required. Your vehicle may also have
an internal thermostat in the plug end of the cord.
This will prevent operation of the engine coolant heater
when the temperature is at or above 0°F (−18°C) as
noted on the cord.
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 it 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 in the area where you will
be parking your vehicle. The dealer can give you the
best advice for that particular area.
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Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic transmission
and features an electronic shift position indicator
within the instrument panel cluster. This display must
be powered anytime the shift lever is capable of
being moved out of PARK (P).
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.
{CAUTION:
It is 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.
Do not leave your vehicle when the engine
is running unless you have to. If you have
left the engine running, the vehicle can move
suddenly. You or others could be injured.
CAUTION: (Continued)
CAUTION: (Continued)
To be sure your vehicle will not move, even
when you are on fairly level ground, always
set your parking brake and move the shift
lever to PARK (P). SeeShifting Into Park (P)
on page 2-32. If you are pulling a trailer, see
Towing a Trailer on page 4-60.
{CAUTION:
If you have four-wheel drive, your vehicle
will be free to roll — even if your shift lever
is in PARK (P) — if your transfer case is in
NEUTRAL. So, be sure the transfer case is
in a drive gear, two-wheel high, four-wheel
high or four-wheel low — not in NEUTRAL.
SeeShifting Into Park (P) on page 2-32.
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REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out of
snow, ice or sand without damaging your transmission,
seeIf Your Vehicle is Stuck in Sand, Mud, Ice or
Snow on page 4-44.
NEUTRAL (N):In this position, your engine does not
connect with the wheels. To restart when you are
already moving, use NEUTRAL (N) only. Also, use
NEUTRAL (N) when your two-wheel drive vehicle
is being towed.
{CAUTION:
Shifting into a drive gear while your engine is
running at high speed is dangerous. Unless
your foot is rmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.Notice:Shifting out of PARK (P) or NEUTRAL (N)
with the engine running at high speed may damage
the transmission. The repairs would not be covered
by your warranty. Be sure the engine is not running
at high speed when shifting your vehicle.
DRIVE (D):This position is for normal driving.
If you need more power for passing, and you are:
Going less than about 35 mph (56 km/h), push
your accelerator pedal about halfway down.
Going about 35 mph (56 km/h) or more, push
the accelerator all the way down.
You will shift down to the next gear and have
more power.
DRIVE (D) can be used when towing a trailer, carrying
a heavy load, driving on steep hills or for off-road
driving. You may want to shift the transmission to
THIRD (3) or, if necessary, a lower gear selection if
the transmission shifts too often.
THIRD (3):This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).
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SECOND (2):This position gives you more power
but lower fuel economy. You can use SECOND (2) on
hills. It can help control your speed as you go down
steep mountain roads, but then you would also want
to use your brakes off and on.
If you manually select SECOND (2) in a light duty
automatic transmission, the transmission will drive in
second gear. You may use this feature for reducing the
speed of the rear wheels when you are trying to start
your vehicle from a stop on slippery road surfaces.
FIRST (1):This position gives you even more
power (but lower fuel economy) than SECOND (2).
You can use it on very steep hills, or in deep snow or
mud. If the shift lever is put in FIRST (1) while the
vehicle is moving forward, the transmission will not shift
into rst gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator pedal
may damage the transmission. If you are stuck,
do not spin the tires. When stopping on a hill, use
the brakes to hold the vehicle in place.
On cold days, approximately 32°F (0°C) or colder,
your transmission is designed to shift differently until
the engine reaches normal operating temperature.
This is intended to improve heater performance.Tow/Haul Mode
Your vehicle may be equipped with a Tow/Haul mode.
If so, the selector button is located on the end of the
column shift lever. You can use this feature to assist
when towing or hauling a heavy load. SeeTowing a
Trailer on page 4-60for more information.
2-25

When Tow/Haul mode
is selected the
Tow/Haul indicator
light will illuminate.
The Tow/Haul mode also interacts with the Autoride
®
feature, if equipped, to enhance the ride when trailering
or with a loaded vehicle. SeeAutoride®on page 4-60.
Four-Wheel Drive
If your vehicle has four-wheel drive, you will see the
buttons shown below. You can send your engine’s
driving power to all four wheels for extra traction.
To get the most satisfaction out of four-wheel drive,
you must be familiar with its operation. Read the
part that follows before using four-wheel drive.
Notice:Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive Low for
an extended period of time may cause premature
wear on your vehicle’s powertrain. Do not drive on
clean, dry pavement in Four-Wheel Drive High or
Four-Wheel-Drive Low for extended periods of time.The transfer case buttons
are located to the left
of the instrument panel
cluster.
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle
to lock or unlock is normal.
For information on StabiliTrak
®, seeStabiliTrak®
System on page 4-9.
Use these buttons to shift into and out of
four-wheel drive.
2-26

If the SERVICE 4WD message stays on, you should
take your vehicle to your dealer for service. See “Service
4WD message” underDIC Warnings and Messages
on page 3-56.
Shifting Into Four-Wheel High or
AUTO 4WD (Automatic Four-Wheel Drive)
Press and release the Four-Wheel High or AUTO
4WD button. This can be done at any speed, except
when shifting from Four-Wheel Low, and the indicator
light will ash while shifting. It will remain on when
the shift is completed.
Shifting Into Two-Wheel High
Press and release the Two-Wheel High button.
This can be done at any speed, except when
shifting from Four-Wheel Low.
Shifting Into Four-Wheel Low
To shift to the Four-Wheel Low position, the ignition
must be in RUN and the vehicle must be stopped
or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N). The preferred
method for shifting into four-wheel low is to have
your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).Press and release the Four-Wheel Low button.
You must wait for the four-wheel low indicator light
to stop ashing and remain on before shifting your
transmission in gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To
help avoid damaging your vehicle, always wait for
the Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL with the engine running.
If the Four-Wheel Low button is pressed when your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will ash for 30 seconds and not complete
the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds the transfer case will shift to
Four-Wheel High mode.
2-28

Shifting Out of Four-Wheel Low
To shift from Four-Wheel Low to Four-Wheel High,
AUTO 4WD or Two-Wheel High, your vehicle must be
stopped or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N) and the ignition in RUN.
The preferred method for shifting out of Four-Wheel
Low is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the Four-Wheel
High, AUTO 4WD or Two-Wheel High button. You must
wait for the Four-Wheel High, AUTO 4WD or Two-Wheel
High indicator light to stop ashing and remain on
before shifting your transmission into gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging your vehicle, always wait for the
Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.It is typical for your vehicle to exhibit signicant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL with the engine running.
If the Four-Wheel High, AUTO 4WD or Two-Wheel High
switch is pressed when your vehicle is in gear and/or
moving, the Four-Wheel High, AUTO 4WD or Two-Wheel
High indicator light will ash for 30 seconds but will not
complete the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
2-29

Shifting into NEUTRAL
To shift the transfer case to NEUTRAL do the following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake. SeeParking Brake on
page 2-31for more information.
3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel High.
6. Simultaneously press and hold the Two-Wheel High
and Four-Wheel Low buttons for 10 seconds.
The NEUTRAL light will come on when the transfer
case shift to NEUTRAL is complete.
7. If the engine is running, verify that the transmission
is in NEUTRAL (N) by shifting the transmission
to REVERSE (R) for one second, then shift
the transmission to DRIVE (D) for one second.
8. Turn the ignition to ACCESSORY, which will turn
the engine off.
9. Place the transmission shift lever in PARK (P).
10. Turn the ignition to LOCK.
Shifting Out of NEUTRAL
To shift out of NEUTRAL do the following:
1. Set the parking brake and apply the regular
brake pedal.
2. Shift the transmission to NEUTRAL (N) and turn
the ignition to RUN with the engine off.
3. Press the button for the desired transfer case
shift position (Two-Wheel High, Four-Wheel High,
AUTO 4WD, or Four-Wheel Low).
After the transfer case has shifted out of
NEUTRAL the NEUTRAL light will go out.
4. Release the parking brake.
Notice:Shifting the transmission into gear
before the Four-Wheel Low indicator light has
stopped ashing could damage the transfer case.
To help avoid damaging your vehicle, always
wait for the Four-Wheel Low indicator light to stop
ashing before shifting the transmission into gear.
5. Start the engine and shift the transmission to
the desired position.
Excessively shifting the transfer case into or out of
the different modes may cause the transfer case to enter
the shift protection mode. This will protect the transfer
case from possible damage and will only allow the
transfer case to respond to one shift per 10 seconds.
The transfer case may stay in this mode for up to
three minutes.
2-30