2003 GMC YUKON engine

Adjustable Throttle and Brake Pedal
If your vehicle is equipped with this feature, you can
change the position of the throttle and brake pedals.
This feature is designed for shorter drivers, since
the pedals can not move farther away from the standard
position, but can move forward for better pedal reach.
The vehicle must be in PARK (P) for this feature to
operate.
The switch used to adjust
the pedals is located on
the driver’s side door
panel.
Press the arrow at the end of the switch closest to you
to move the pedals closer to your body. Press the
arrow at the far end of the switch to move the pedals
away from your body.
Engine Coolant Heater
In very cold weather, 0°F
(−18°C) or colder, the
engine coolant heater can
help. You’ll 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.
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2003 - Yukon/Yukon XL

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 steeringuid
reservoir. If you have a diesel engine, refer to
diesel supplement for location.
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 afire. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord
won’t 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 don’t, 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’ll be parking your
vehicle. The dealer can give you the best advice for that
particular area.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’s the
best position to use when you start your engine
because your vehicle can’t move easily.
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{CAUTION:
It is dangerous to get out of your vehicle if the
shift lever is not fully in PARK (P) with the
parking brakefirmly set. Your vehicle can roll.
Don’t 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. To
be sure your vehicle won’t move, even when
you’re on fairly level ground, always set your
parking brake and move the shift lever to
PARK (P). See“Shifting Into Park (P)”in the
Index. If you’re pulling a trailer, see“Towing a
Trailer”in the Index.
{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 (2H) or four–wheel high (4H) or
four-wheel low (4L)–not in NEUTRAL. See
″Shifting into Park (P)″in the index.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage your transmission.
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,
see If You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-52.
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2003 - Yukon/Yukon XL

NEUTRAL (N):In this position, your engine doesn’t
connect with the wheels. To restart when you’re 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
“racing”(running at high speed) is dangerous.
Unless your foot isfirmly on the brake pedal,
your vehicle could move very rapidly. You
could lose control and hit people or objects.
Don’t shift into a drive gear while your engine
is racing.
Notice:Damage to your transmission caused by
shifting out of PARK (P) or NEUTRAL (N) with
the engine racing isn’t covered by your warranty.
DRIVE (D):This position is for normal driving. If
you need more power for passing, and you’re:
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’ll 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).
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.
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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 won’t shift intorst
gear until the vehicle is going slowly enough.
Notice:If your wheels won’t turn, don’t try to drive.
This might happen if you were stuck in very deep
sand or mud or were up against a solid object. You
could damage your transmission. Also, if you
stop when going uphill, don’t hold your vehicle there
with only the accelerator pedal. This could overheat
and damage the transmission. Use your brakes
or shift into PARK (P) to hold your vehicle in
position on a hill.
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 4-61for more information.
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2003 - Yukon/Yukon XL

When tow/haul mode is
selected the tow/haul
indicator light will
illuminate.
The tow/haul mode also interacts with the Autoride™
feature, if your vehicle is so equipped, to enhance
the ride when trailering or with a loaded vehicle. See
Autoride™on page 4-60.
Four-Wheel Drive
If your vehicle has four-wheel drive, 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. See
the appropriate text for the transfer case in your
vehicle.
Notice:Driving in the 4-WHEEL HIGH (4HI) or
4-WHEEL LOW (4LO) positions for a long time on
dry or wet pavement could shorten the life of
your vehicle’s drivetrain.
Front Axle Locking Feature
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle to
lock or unlock is normal.
Automatic Transfer Case
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. See″Parking Brake″in the
Index.
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Shifting into 4LO
To shift to the 4 lo position, the ignition must be in RUN
and the vehicle must be stopped or moving less than
3 mph (4.8 km/h) with the transmission in NEUTRAL (N).
The preferred method for shifting into 4LO is to have
your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press
and release the 4 lo switch. You must wait for the
4LO indicator light to stopashing and remain
illuminated before shifting your transmission in gear.
Notice:Shifting the transmission into gear before
the 4LO indicator light has stoppedflashing
could damage the transfer case. To help avoid
damaging your vehicle, always wait for the
4LO indicator light to stopflashing before shifting
your transmission into gear.
It is typical for your vehicle to exhibit signicant
engagment noise and bump when shifting between
4LO and 4HI ranges or from NEUTRAL with the engine
running.
If the 4 lo switch is pressed when your vehicle is in gear
and/or moving, the 4LO indicator light willash for
30 seconds and not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds
the transfer case will return to the setting last chosen.
Shifting Out of 4LO
To shift from 4LO to 4HI, AUTO 4WD or 2HI your
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N) and
the ignition in RUN. The preferred method for shifting out
of 4LO is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the 4HI,
AUTO 4WD or 2HI switch. You must wait for the 4HI,
AUTO 4WD or 2HI indicator light to stopashing
and remain illuminated before shifting your transmission
into gear.
Notice:Shifting the transmission into gear before
the 4LO indicator light has stoppedflashing
could damage the transfer case. To help avoid
damaging your vehicle, always wait for the
4LO indicator light to stopflashing before shifting
your transmission into gear.
It is typical for your vehicle to exhibit signicant
engagment noise and bump when shifting between
4LO and 4HI ranges or from NEUTRAL with the engine
running.
If the 4HI, AUTO 4WD or 2HI switch is pressed when
your vehicle is in gear and/or moving, the 4HI,
AUTO 4WD or 2HI indicator light willash for
30 seconds but will not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and
the transmission is in NEUTRAL (N).
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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.
3. Start the vehicle or turn the ignition to RUN.
4. Connect the vehicle to the towing vehicle.
5. Put the transmission in NEUTRAL (N).
6. Shift the transfer case to 2HI.
7. Simultaneously press and hold the 2HI and 4LO
buttons for 10 seconds. The red NEUTRAL light
will come on when the transfer case shift to
NEUTRAL is complete.
8. Shift the transmission to REVERSE (R) for one
second, then shift the transmission to DRIVE (D)
for one second.
9. Turn the ignition off.
10. Place the transmission shift lever in PARK (P).
11. Release the parking brake prior to towing.
Shifting Out of NEUTRAL
To shift out of NEUTRAL:
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 (2HI, 4HI, AUTO 4WD OR 4 LO).
4. After the transfer case has shifted out of NEUTRAL
the red light will go out.
5. You may 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.
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