2002 GMC SIERRA steering

1-24 How the Air Bag System Works
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.

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CAUTION:
If something is between an occupant and an air
bag, the bag might not inflate properly or it
might force the object into that person causing
severe injury or even death. The path of an
inflating air bag must be kept clear. Don't put
anything between an occupant and an air bag,
and don't attach or put anything on the steering
wheel hub or on or near any other air bag
covering.
When should an air bag inflate?
An air bag is designed to inflate in a moderate to severe
frontal or near
-frontal crash. The air bag will inflate
only if the impact speed is above the system's designed
ªthreshold level.º If your vehicle goes straight into a
wall that doesn't move or deform, the threshold level is
about 9 to 16 mph (14 to 26 km/h). The threshold level
can vary, however, with specific vehicle design, so that
it can be somewhat above or below this range. If your
vehicle strikes something that will move or deform, such
as a parked car, the threshold level will be higher.The air bag is not designed to inflate in rollovers, rear
impacts, or in many side impacts because inflation
would not help the occupant.
In any particular crash, no one can say whether an air
bag should have inflated simply because of the damage
to a vehicle or because of what the repair costs were.
Inflation is determined by the angle of the impact and
how quickly the vehicle slows down in frontal or
near
-frontal impacts.
The air bag system is designed to work properly under a
wide range of conditions, including off
-road usage.
Observe safe driving speeds, especially on rough terrain.
As always, wear your safety belt. See ªOff
-Road
Drivingº in the Index for more tips on off
-road driving.
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.

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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 vents in the deflated air bags. Air bag
inflation doesn't prevent the driver from seeing or from
being able to steer the vehicle, nor does it stop people
from leaving the vehicle.
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 door.
In many crashes severe enough to inflate an 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.

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Your vehicle is equipped with a crash sensing and
diagnostic module, which records information about
the air bag system. The module records information
about the readiness of the system, when the system
commands air bag inflation and driver's safety belt
usage at deployment. The module also records speed,
engine rpm, brake and throttle data.

Let only qualified technicians work on your air bag
system. Improper service can mean that your 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.
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.

2-18
When starting your engine in very cold weather
(below 0
F or
-18
C), do this:
1. With your foot off the accelerator pedal, turn the ignition
key to START and hold it there up to 15 seconds.
When the engine starts, let go of the key.
2. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Try pushing your accelerator pedal all the way to
the floor and holding it there as you hold the key in
START for about three seconds. When the engine
starts, let go of the key and accelerator. If the vehicle
starts briefly but then stops again, do the same thing,
but this time keep the pedal down for five or six
seconds. This clears the extra gasoline from the engine.
NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
Engine Coolant Heater (If Equipped)
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.
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 fluid reservoir.

2-29
Locking Rear Axle
If your vehicle has this feature, your locking rear axle
can give you additional traction on snow, mud, ice, sand
or gravel. It works like a standard axle most of the time,
but when one of the rear wheels has no traction and
the other does, this feature will allow the wheel with
traction to move the vehicle.
All-Wheel Drive
With this feature, engine power is sent to all four wheels
when extra traction is needed.
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.
QUADRASTEER (4WS)
The QUADRASTEER System has a control and
diagnostic module that monitors and records current
system status and operational information.
If your vehicle is equipped with the 4WS system it has
the ability to steer the vehicle with all four wheels.
Once this mode is selected, it is recommended to leave
the vehicle in this mode at all times.
The 4WS system is equipped with three different
driving modes:

Two wheel steering (2WS)

Four wheel steering (4WS)

Four wheel steering with a trailer mode (4WS TOW)

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The switch is located on the instrument panel.
2WS: In this mode the vehicle will operate like any
other vehicle with two wheel steering. If you want to
use 2WS and your vehicle is not in this mode, press the
4 Wheel Steer button until the 2WS indicator, located to
the right of the 4 Wheel Steer button, lights up. If the
2WS indicator is flashing you will have to center the
steering wheel by turning it to the left or right.
4WS: In this mode all four wheels will help steer the
vehicle. If you want to use 4WS, and your vehicle is not
in this mode, press the 4 Wheel Steer button, until the
4WS indicator, located to the right of the 4 Wheel Steer
button, lights up. If the 4WS indicator is flashing you
will have to center the steering wheel by turning it to the
left or right.Slower Speed Mode (below 40 mph/64 kph)
At slower speeds the steering will operate in the lower
speed mode. This means the front and rear wheels will
turn in opposite directions. This helps the vehicle make
tighter turns, such as during parking, cornering and
turning into tight spaces.

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Higher Speed Mode (40 mph/64 kph and above)
At higher speeds the steering will operate in the higher
speed mode. This means the front and rear wheels will
turn in the same direction. This improves stability of the
vehicle during lane changes and sweeping turns.4WS TOW: The 4WS TOW mode provides enhanced
stability allowing the trailer to follow the path of the tow
vehicle more closely, especially during lane changes.
In this mode the system operates much like the
4WS mode, but is enhanced for trailer towing.
It is recommended for all types and weights of trailers.
To engage the 4WS TOW mode, press the 4 Wheel Steer
button until the 4WS and TOW indicators light up on
the instrument panel. If the TOW indicator is flashing
you will have to center the steering wheel by turning it
to the left or right. While in the 4WS TOW mode, it is
possible the steering wheel may be slightly off center.