2003 GMC SIERRA trailer

Passlock®
Your vehicle is equipped with the
Passlock®theft-deterrent system.
Passlock
®is a passive theft-deterrent system.
Passlock®enables fuel if the ignition lock cylinder is
turned with a valid key. If a correct key is not used or the
ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security lightashes,
wait until the light stopsashing before trying to restart
the engine. Remember to release the key from
START as soon as the engine starts.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the
engine off. However, your Passlock
®system is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by Passlock
®at this
time. You may also want to check the fuse (see
Fuses and Circuit Breakers on page 5-91.) See your
dealer for service.
In an emergency, call the GM Roadside Assistance
Center. SeeRoadside Assistance Program on page 7-5
under Customer Assistance Information.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle doesn’t need an elaborate
“break-in.”But it will perform better in the long run
if you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the first 500 miles (805 km).
•Don’t drive at any one speed — fast or
slow — for the first 500 miles (805 km).
Don’t make full-throttle starts.
•Avoid making hard stops for the first 200 miles
(322 km) or so. During this time your new
brake linings aren’t yet broken in. Hard stops
with new linings can mean premature wear and
earlier replacement. Follow this breaking-in
guideline every time you get new brake linings.
•Don’t tow a trailer during break-in. See “Towing
a Trailer” in the Index for more information.
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2003 - Sierra Denali

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

Parking Brake
To set the parking brake, hold the regular brake pedal
down with your right foot. Push down the parking
brake pedal with your left foot.
A chime will activate and the warning light willash
when the parking brake is applied and the vehicle
is moving at least 3 mph (5 km/h) for at least three
seconds.To release the parking brake, hold the regular brake
pedal down. Pull the bottom edge of the lever, located
above the parking brake pedal, with the parking
brake symbol, to release the parking brake.
If the ignition is on when the parking brake is released,
the brake system warning light will go off.
Notice:Driving with the parking brake on can
cause your rear brakes to overheat. You may have
to replace them, and you could also damage
other parts of your vehicle.
If you are towing a trailer and are parking on any hill,
seeTowing a Trailer on page 4-53.
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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

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

SeeDriver Information Center (DIC) on page 3-42for
further information.
If the transmissionfluid reaches temperatures of
approximately 275°F (135°C) or greater, the Driver
Information Center will display a TRANS HOT IDLE
ENG warning message. Pull the vehicle off the roadway
when it is safe to do so. Set the parking brake, place
the transmission in PARK (P) and allow the engine
to idle until the transmission temperature falls below
260°F (127°C). If the transmission continues to operate
above 265°F (130°C), contact your nearest dealer or
the GM Roadside Assistance Center. SeeRoadside
Assistance Program on page 7-5.
Notice:If you keep driving your vehicle with the
transmission temperature gage above the normal
operating range, you can damage the transmission.
This could lead to costly repairs that may not be
covered under your warranty.
The following situations can cause the transmission to
operate at higher temperatures:
•Towing a trailer
•Hot outside air temperatures
•Hauling a large or heavy load
•Low transmissionfluid level
•High transmissionfluid level
•Restricted airflow to the radiator and the auxiliary
transmission oil cooler (if equipped).A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
on page 6-5for the proper transmission maintenance
intervals.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The Check Engine light comes on to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
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