2003 GMC SIERRA engine

Automatic Transmission Operation
Your vehicle is equipped with an automatic transmission
that features an electronic shift position indicator
located within the instrument panel cluster. This display
is powered anytime the shift lever is capable of being
moved out of PARK (P). SeeFuses and Circuit Breakers
on page 5-91.
There are several different positions for your shift lever.
PARK (P):This position locks your wheels. It’s the
best position to use when you start your engine because
your vehicle can’t 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 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.
CAUTION: (Continued)
CAUTION: (Continued)
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.
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,
seeIf You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-44.
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 vehicle is being towed.
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2003 - Sierra Denali

{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 (55 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (55 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 occasionally.
If you manually select SECOND (2), 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 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.
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2003 - Sierra Denali

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.
The switch is located on the end of the column shift
lever. You can use this feature to assist when towing or
hauling a heavy load.When tow/haul is activated
the tow/haul symbol will
illuminate on the
instrument panel cluster.
SeeTow/Haul Modeunder
Towing a Trailer on
page 4-53for more
information.
All-Wheel Drive
With this feature, engine power is sent to all four wheels
all the time.
This is like four-wheel drive, but there is no separate
lever or switch to engage or disengage the front axle.
It is fully automatic, and adjusts itself as needed for road
conditions.
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2003 - Sierra Denali

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 brakefirmly 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 won’t
move, even when you’re on fairly level ground,
use the steps that follow. With four-wheel
drive, if your transfer case is in NEUTRAL,
your vehicle will be free to roll, even if your
shift lever is in PARK (P). So, be sure the
transfer case is in a drive gear—not in
NEUTRAL. If you’re pulling a trailer, see
“Towing a Trailer”in the Index.1. Hold the brake pedal down with your right foot and
set the parking brake.
2. Move the shift lever into PARK (P) like this:
Pull the shift lever toward you.
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2003 - Sierra Denali

Move the lever up as far as it will go.
3. Turn the ignition key to LOCK.
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 brakefirmly set.
And, if you leave the vehicle with the engine
running, it could overheat and even catchfire.
You or others could be injured. Don’t 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 isrmly set before you leave it. After you
move the shift lever into PARK (P), hold the regular
brake pedal down. Then, see if you can move the shift
lever away from PARK (P) withoutrst pulling it
toward you. If you can, it means that the shift lever
wasn’t fully locked into PARK (P).
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2003 - Sierra Denali

Parking Over Things That Burn
{CAUTION:
Things that can burn could touch hot exhaust
parts under your vehicle and ignite. Don’t park
over papers, leaves, dry grass or other things
that can burn.
Engine Exhaust
{CAUTION:
Engine exhaust can kill. It contains the gas
carbon monoxide (CO), which you can’t see or
smell. It can cause unconsciousness and death.
You might have exhaust coming in if:
•Your exhaust system sounds strange or
different.
•Your vehicle gets rusty underneath.
•Your vehicle was damaged in a collision.
•Your vehicle was damaged when driving
over high points on the road or over road
debris.
•Repairs weren’t done correctly.
•Your vehicle or exhaust system had been
modified improperly.
If you ever suspect exhaust is coming into your
vehicle:
•Drive it only with all the windows down to
blow out any CO; and
•Have your vehiclefixed immediately.
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2003 - Sierra Denali

Running Your Engine While You
Are Parked
It’s better not to park with the engine running. But if you
ever have to, here are some things to know.
{CAUTION:
Idling the engine with the climate control
system off could allow dangerous exhaust into
your vehicle. See the earlier Caution under
“Engine Exhaust.”
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the fan is at the highest setting. One place this
can happen is a garage. Exhaust—with
CO—can come in easily. NEVER park in a
garage with the engine running.
Another closed-in place can be a blizzard. See
“Winter Driving”in the Index.
{CAUTION:
It can be 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’ve 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).
Follow the proper steps to be sure your vehicle won’t
move. SeeShifting Into Park (P) on page 2-23.
If you’re pulling a trailer, seeTowing a Trailer on
page 4-53.
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2003 - Sierra Denali

Keep the original transmitter for use in other vehicles as
well as for future HomeLink®programming. It is also
recommended that upon the sale of the vehicle,
the programmed HomeLink
®buttons should be erased
for security purposes. Refer to“Erasing HomeLink®
Buttons”or, for assistance, contact HomeLink®on the
internet at: www.homelink.com or by calling
1-800-355-3515.
Be sure that people and objects are clear of the garage
door or gate operator you are programming. When
programming a garage door, it is advised to park outside
of the garage.
It is recommended that a new battery be installed in
your hand-held transmitter for quicker and more
accurate transmission of the radio frequency.
Your vehicle’s engine should be turned off while
programming the transmitter. Follow these steps to
program up to three channels:
1. Press and hold down the two outside buttons,
releasing only when the indicator light begins to
ash, after 20 seconds. Do not hold down the
buttons for longer than 30 seconds and do not
repeat this step to program a second and/or third
transmitter to the remaining two HomeLink
®buttons.
2. Position the end of your hand-held transmitter about
1 to 3 inches (3 to 8 cm) away from the HomeLink
®
buttons while keeping the indicator light in view.3. Simultaneously press and hold both the desired
button on HomeLink
®and the hand-held transmitter
button. Do not release the buttons until Step 4
has been completed.
Some entry gates and garage door openers may
require you to substitute Step 3 with the procedure
noted in“Gate Operator and Canadian
Programming”later in this section.
4. The indicator light willash slowly atrst and then
rapidly after HomeLink
®successfully receives the
frequency signal from the hand-held transmitter.
Release both buttons.
5. Press and hold the newly-trained HomeLink
®button
and observe the indicator light.
If the indicator light stays on constantly,
programming is complete and your device should
activate when the HomeLink
®button is pressed and
released.
To program the remaining two HomeLink
®buttons,
begin with Step 2 under“Programming HomeLink®.”
Do not repeat Step 1 as this will erase all of the
programmed channels.
If the indicator light blinks rapidly for two seconds
and then turns to a constant light, continue with
Steps 6 through 8 following to complete the
programming of a rolling-code equipped device
(most commonly, a garage door opener).
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2003 - Sierra Denali