GMC YUKON 2001 Service Manual

1-28
The best way to protect the fetus is to protect the
mother. When a safety belt is worn properly, it's more
likely that the fetus won't be hurt in a crash. For
pregnant women, as for anyone, the key to making
safety belts effective is wearing them properly.
Right Front Passenger Position
To learn how to wear the right front passenger's
safety belt properly, see ªDriver Positionº earlier
in this section.
The right front passenger's safety belt works the same
way as the driver's safety belt
-- except for one thing.
If you ever pull the shoulder portion of the belt out
all the way, you will engage the child restraint locking
feature. If this happens, just let the belt go back all the
way and start again.
Air Bag Systems
This part explains the frontal and side impact air
bag systems.
Your vehicle has four air bags
-- a frontal air bag
for the driver, another frontal air bag for the right front
passenger, a side impact air bag for the driver, and
another side impact air bag for the right front passenger.Frontal air bags are designed to help reduce the risk
of injury from the force of an inflating frontal air bag.
But these air bags must inflate very quickly to do their
job and comply with federal regulations.
Here are the most important things to know about the
air bag systems:
CAUTION:
You can be severely injured or killed in a crash
if you aren't wearing your safety belt
-- even if
you have air bags. Wearing your safety belt
during a crash helps reduce your chance of
hitting things inside the vehicle or being ejected
from it. Air bags are ªsupplemental restraintsº
to the safety belts. All air bags are designed to
work with safety belts but don't replace them.
CAUTION: (Continued)

1-29
CAUTION: (Continued)
Frontal air bags for the driver and right front
passenger are designed to work only in moderate
to severe crashes where the front of your vehicle
hits something. They aren't designed to inflate
at all in rollover, rear, side or low
-speed frontal
crashes. And, for unrestrained occupants, frontal
air bags may provide less protection in frontal
crashes than more forceful air bags have
provided in the past. The side impact air bags for
the driver and right front passenger are designed
to inflate only in moderate to severe crashes
where something hits the side of your vehicle.
They aren't designed to inflate in frontal,
in rollover or in rear crashes. Everyone in
your vehicle should wear a safety belt
properly
-- whether or not there's an air
bag for that person.
CAUTION:
Both frontal and side impact air bags inflate
with great force, faster than the blink of an eye.
If you're too close to an inflating air bag, as you
would be if you were leaning forward, it could
seriously injure you. Safety belts help keep you in
position for air bag inflation before and during a
crash. Always wear your safety belt, even with
frontal air bags. The driver should sit as far back
as possible while still maintaining control of the
vehicle. Front occupants should not lean on or
sleep against the door.

1-30
CAUTION:
Anyone who is up against, or very close to, any
air bag when it inflates can be seriously injured
or killed. Air bags plus lap
-shoulder belts offer
the best protection for adults, but not for young
children and infants. Neither the vehicle's safety
belt system nor its air bag system is designed
for them. Young children and infants need the
protection that a child restraint system can
provide. Always secure children properly in your
vehicle. To read how, see the part of this
manual called ªChildren.º
There is an air bag
readiness light on the
instrument panel, which
shows the air bag symbol.
The system checks the air bag electrical system for
malfunctions. The light tells you if there is an electrical
problem. See ªAir Bag Readiness Lightº in the Index
for more information.

1-31 How the Air Bag Systems Work
Where are the air bags?
The driver's frontal air bag is in the middle of the
steering wheel.
The right front passenger's frontal air bag is in the
instrument panel on the passenger's side.
The driver's side impact air bag is in the side of the
driver's seatback closest to the door.

1-32
The right front passenger's side impact air bag is in the
side of the passenger's seatback closest to the door.
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. 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 and don't let seat covers block the
inflation path of a side impact air bag.

1-33
When should an air bag inflate?
The driver's and right front passenger's frontal air bags
are designed to inflate in moderate to severe frontal or
near
-frontal crashes. But they are designed to 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 driver's and right front passenger's frontal
air bags are not designed to inflate in rollovers, side
impacts, or rear impacts, because inflation would not
help the occupant.
The side impact air bags are designed to inflate in
moderate to severe side crashes. A side impact air bag
will inflate if the crash severity is above the system's
designed ªthreshold level.º The threshold level can vary
with specific vehicle design. Side impact air bags are not
designed to inflate in frontal or near
-frontal impacts,
rollovers or rear impacts, because inflation would not
help the occupant. A side impact air bag will only
deploy on the side of the vehicle that is struck.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. For
frontal air bags, inflation is determined by the angle of
the impact and how quickly the vehicle slows down in
frontal and near
-frontal impacts. For side impact air
bags, inflation is determined by the location and severity
of the impact.
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. For both
frontal and side impact air bags, 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, instrument panel and the side of the front
seatbacks closest to the door.

1-34
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. In moderate to severe side
collisions, even belted occupants can contact the inside
of the vehicle. The air bag supplements 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 the frontal air
bags would not help you in many types of collisions,
including rollovers, rear impacts, and side impacts,
primarily because an occupant's motion is not toward
the air bag. Side impact air bags would not help you in
many types of collisions, including frontal or near
frontal collisions, rollovers, and rear 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 for
the driver's and right front passenger's frontal air bags,
and only in moderate to severe side collisions for the
driver's and right front passenger's side impact air bags.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, the instrument
panel for the right front passenger's bag, the side of the
seatback closest to the door for the driver and right front
passenger's side impact air bags
-- 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.

1-35
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.
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 an
air bag inflates, 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 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, 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 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, or the air bag
covering on the driver's and right front
passenger's seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right
front passenger's air bag, or both the air bag
module and seatback for the driver's and right
front passenger's side impact air bag. Do not
open or break the air bag coverings.

1-36 Servicing Your Air Bag-Equipped Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag systems in several places
around your vehicle. Your dealer and the service manual
have information about servicing your vehicle and the
air bag systems. To purchase a service manual, see
ªService and Owner Publicationsº in the Index.
CAUTION:
For up to two minutes after the ignition key is
turned off and the battery is disconnected, an
air bag can still inflate during improper service.
You can be injured if you are close to an air bag
when it inflates. Avoid yellow connectors. They
are probably part of the air bag systems. Be sure
to follow proper service procedures, and make
sure the person performing work for you is
qualified to do so.
The air bag systems do not need regular maintenance.
Adding Equipment to Your
Air Bag-Equipped Vehicle
Q:If I add a push bumper or bicycle rack to the
front of my vehicle, will it keep the air bags
from working properly?
A:As long as the push bumper or bicycle rack is
attached to your vehicle so that the vehicle's basic
structure isn't changed, it's not likely to keep the
air bags from working properly in a crash.
Q:Is there anything I might add to the front or
sides of the vehicle that could keep the air bags
from working properly?
A:Yes. If you add things that change your vehicle's
frame, bumper system, front end or side sheet metal
or height, they may keep the air bag system from
working properly. Also, the air bag system may not
work properly if you relocate any of the air bag
sensors. If you have any questions about this,
you should contact Customer Assistance before
you modify your vehicle. The phone numbers and
addresses for Customer Assistance are in Step Two
of the Customer Satisfaction Procedure in this
manual. See ªCustomer Satisfaction Procedureº
in the Index.

1-37
Q:What if I add a snow plow? Will it keep the
air bags from working properly?
A:We've designed our air bag systems to work
properly under a wide range of conditions,
including snow plowing with vehicles equipped
with the optional Snow Plow Prep Package
(RPO VYU). But don't change or defeat the
snow plow's ªtripping mechanism.º If you do,
it can damage your snow plow and your vehicle,
and it may cause an air bag inflation.
Lap Belt
If your vehicle has front and rear bench seats, someone
can sit in the center positions.
When you sit in a center seating position, you have a lap
safety belt, which has no retractor. To make the belt
longer, tilt the latch plate and pull it along the belt.