Page 63 of 408
Where Are the Air Bags?
The driver’s air bag is in the middle of the steering
wheel.The right front passenger’s air bag is in the instrument
panel on the passenger’s side.
1-57
2003 - Sierra Denali
Page 65 of 408

Seat Position Sensors
Vehicle’s with dual stage air bags are also equipped
with special sensors which enable the sensing system to
monitor the position of both the driver and passenger
front seats. The seat position sensor provides
information which is used to determine if the air bags
should deploy at a reduced level or at full depoyment.
What Makes an Air Bag Inflate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. The
sensing system triggers a release of gas from the
inflator, which inflates the air bag. The inflator, air bag,
and related hardware are all part of the air bag
modules inside the steering wheel and in the instrument
panel in front of the right front passenger.
How Does an Air Bag Restrain?
In moderate to severe frontal or near-frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. Air bags supplement the
protection provided by safety belts. Air bags distribute
the force of the impact more evenly over the occupant’s
upper body, stopping the occupant more gradually.But air bags would not help you in many types of
collisions, including rollovers, rear impacts and many
side impacts, primarily because an occupant’s motion is
not toward those air bags. Air bags should never be
regarded as anything more than a supplement to safety
belts, and then only in moderate to severe frontal or
near-frontal collisions.
What Will You See After an Air Bag
Inflates?
After an air bag inflates, it quickly deflates, so quickly
that some people may not even realize the air bag
inflated. Some components of the air bag module–the
steering wheel hub for the driver’s air bag, or the
instrument panel for the right front passenger’s
bag–will be hot for a short time. The parts of the bag
that come into contact with you may be warm, but
not too hot to touch. There will be some smoke and dust
coming from the vents in the deflated air bags.
Air bag inflation doesn’t prevent the driver from seeing
or being able to steer the vehicle, nor does it stop
people from leaving the vehicle.
1-59
2003 - Sierra Denali
Page 66 of 408

{CAUTION:
When an air bag inflates, there is dust in the
air. This dust could cause breathing problems
for people with a history of asthma or other
breathing trouble. To avoid this, everyone in
the vehicle should get out as soon as it is safe
to do so. If you have breathing problems but
can’t get out of the vehicle after an air bag
inflates, then get fresh air by opening a
window or a door. If you experience breathing
problems following an air bag deployment, you
should seek medical attention.
In many crashes severe enough to inflate the air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from the
right front passenger air bag.
•Air bags are designed to inflate only once. After
they inflate, you’ll need some new parts for your
air bag system. If you don’t get them, the air
bag system won’t be there to help protect you in
another crash. A new system will include air
bag modules and possibly other parts. The service
manual for your vehicle covers the need to
replace other parts.
•Your vehicle is equipped with electronic frontal
sensors which help the sensing system distinguish
between a moderate and a more severe frontal
impact. Your vehicle is also equipped with a crash
sensing and diagnostic module, which records
information about the frontal air bag system. The
module records information about the readiness of
the system and when the system commands
are bag inflation. It records the status of the driver’s
safety belt usage in a crash in which the air bag
deploys or a crash in which the air bag nearly
deploys. The module also records speed, engine
RPM, brake and throttle data.
•Let only qualified technicians work on your air bag
systems. Improper service can mean that an air
bag system won’t work properly. See your dealer for
service.
Notice:If you damage the covering for the driver’s
or the right front passenger’s air bag, the bag
may not work properly. You may have to replace the
air bag module in the steering wheel or both the
air bag module and the instrument panel for
the right front passenger’s air bag. Do not open or
break the air bag coverings.
1-60
2003 - Sierra Denali
Page 67 of 408
Air Bag Off Switch
Your vehicle has a switch on the instrument panel that
you can use to turn off the right front passenger’s
air bag. The switch will look like one of the following
illustrations.
United States with Passenger Sensing System
United States without Passenger Sensing System
1-61
2003 - Sierra Denali
Page 72 of 408

Passenger Sensing System
If your rearview mirror has one of the indicators pictured
in the following illustrations, your vehicle has a
passenger sensing system. The indicator will be visible
when you turn your ignition key to RUN or START.
The words ON and OFF or the symbol for on and off,
will be visible on the rearview mirror during the system
check. When the system check is complete, either
the word ON or the word OFF, or the symbol for on or
the symbol for off will be visible. SeePassenger Air
Bag Status Indicator on page 3-31. If your rearview
mirror does not have either of the indicators pictured
below, then your vehicle does not have the passenger
sensing system.The passenger sensing system will turn off the right
front passenger’s frontal air bag under certain
conditions. The driver’s air bag and the side air bags
are not part of the passenger sensing system. In
addition to the passenger sensing system, your vehicle
also has an air bag off switch located on the instrument
panel as required by the government.
The passenger sensing system works with sensors that
are part of the right front passenger’s seat and safety
belt. The sensors are designed to detect the presence of
a properly seated occupant and determine if the
passenger’s frontal air bag should be enabled (may
inflate) or not.
Accident statistics show that children are safer if they
are restrained in the rear rather than the front seat.
General Motors, therefore, recommends that child
restraints be secured in a rear seat, including an infant
riding in a rear-facing infant seat, a child riding in a
forward-facing child seat and an older child riding in a
booster seat. Never put a child in rear-facing child Passenger Air Bag Status Indicator–United States
Passenger Air Bag Status Indicator−Canada
1-66
2003 - Sierra Denali
Page 75 of 408
{CAUTION:
If the air bag readiness light in the instrument
panel cluster ever comes on and stays on, it
means that something may be wrong with the
CAUTION: (Continued)
CAUTION: (Continued)
air bag system. If this ever happens, have the
vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger’s seat may not have the protection
of the frontal air bag. See “Air Bag Readiness
Light” in the Index for more on this, including
important safety information.
Aftermarket equipment, such as seat covers, can affect
how well the passenger sensing system operates.
You may want to consider not using seat covers or other
aftermarket equipment if your vehicle has the passenger
sensing system.
{CAUTION:
Stowing of articles under the passenger’s seat
or between the passenger’s seat cushion and
seatback may interfere with the proper
operation of the passenger sensing system.
1-69
2003 - Sierra Denali
Page 97 of 408

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.
2-19
2003 - Sierra Denali
Page 99 of 408
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.
2-21
2003 - Sierra Denali