engine Oldsmobile Bravada 2003 s Service Manual

Anti-lock Brake System
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test
is going on. This is normal.
If there’s a problem with
~ the anti-lock brake system,
~ this warning light will
stay on. See
Anti-Lock
Brake System Warning
Light
on page 3-34.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there’s a DRP problem,
both the brake and ABS warning lights will come on
accompanied by a IO-second chime. The lights
and chime will come on each time the ignition
is turned
on until the problem is repaired. See your dealer for
service. Let’s say the
road is wet and you’re driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here’s what
happens with ABS:
A computer senses that wheels are slowing down. If
one of the wheels is about to stop rolling, the computer
will separately work the brakes at each front wheel
and at both rear wheels.
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Traction Assist System (TAS)
Your vehicle has a Traction Assist System (TAS) that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only
if it senses
that one or both of the rear wheels are spinning or
beginning to lose traction. When this happens,
the system reduces engine power to limit wheel spin.
The LOW TRAC light next
to the button will come
on when the TAS is limiting wheel spin. You may feel or
hear the system working, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you
may notice a reduction in acceleration. This is normal
and doesn’t mean there’s a problem with your vehicle.
Examples of these conditions include a hard
acceleration in a turn, an abrupt upshift or downshift
of
the transmission or driving on rough roads.
If your vehicle is in cruise control when the TAS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control. See
Cruise Control Light on page 3-40. When the TRAC
OFF light on the button is on, the TAS is off and will not
limit wheel spin. Adjust your driving accordingly. The TRAC
OFF light
on the button will come on under
the following conditions:
0 The Traction Assist System is turned off, either by
pressing the TAS on/off button or by turning
off
the automatic engagement feature of the TAS.
The transmission is in FIRST (1) gear; TAS will not
operate in this gear. This is normal.
0 The vehicle is driven on an extremely rough road.
When the vehicle leaves the rough surface,
slows
down or stops, the light will go off and TAS will
be on again. This is normal.
A Traction Assist System, Anti-Lock Brake System
or engine-related problem has been detected and
the vehicle needs service.
The Traction Assist System, as delivered from the factory, will automatically come on whenever you start
your vehicle. To limit wheel spin, especially in
slippery road conditions, you should always leave the
system on. But you can turn the TAS
off if you ever need
to. You shouid turn the TAS
off if your vehicle ever
gets stuck in sand, mud or snow and rocking the vehicle
is required.
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To turn the system on or
off, press the TAS OFF/ON
button located near the
shift lever.
If you used the
button to turn the system
off, the TRAC OFF light on
the button will come on
and stay on.
You can turn the system back on at any time by
pressing the button again. The TRAC OFF light on the
button should go off.
If desired, you can change the TAS automatic
engagement feature
so that the system will not come on
automatically when the engine is started. To do
so:
1.
Park the vehicle with the ignition off and the
2. Turn the ignition to RUN; do not start the engine.
3. Apply the brake pedal, press the accelerator
transmission in
PARK (P).
pedal
to the floor and then press the TAS OFF/ON
button and hold it down for at least six seconds.
4. Release the TAS button and both pedals. The next time you
start your vehicle, the TAS will not
automatically come on. You can restore the automatic
feature by using the same procedure. Whether the TAS
is set
to come on automatically or not, you can always
turn the system on or off by pressing the TAS on/off
button.
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.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
5. Turn off the ignition and wait a few seconds.
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Of course, traction is reduced when water, snow, ice,
gravel or other material
is on the road. For safety, you’ll
want to slow down and adjust your driving
to these
conditions.
It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best
to avoid sudden steering, acceleration
or braking (including engine braking by shifting
to a
lower gear). Any sudden changes could cause the tires
to slide. You may not realize the surface is slippery
until your vehicle is skidding. Learn
to recognize warning
clues
- such as enough water, ice or packed snow
on the road
to make a “mirrored surface” - and slow
down when you have any doubt.
Remember: Any anti-lock brake system (ABS) helps
avoid only the braking skid.
Operating Your All-Wheel-Drive
Vehicle
Off Paved Roads
Many of the same design features that help make your
vehicle responsive on paved roads during poor
weather conditions
- features like the locking rear axle
and all-wheel drive
- help make it much better suited
for off-road use than a conventional passenger
car. Its higher ground clearance also helps your vehicle
step over some off-road obstacles. But your vehicle
doesn’t have features like special underbody shielding and a transfer case low gear range, things that are
usually thought necessary for extended or severe
off-road service. This guide is for operating your vehicle
off paved roads.
Also, see
Braking on page 4-6.
Off-road driving can be great fun. But it does have
some definite hazards. The greatest
of these is
the terrain itself.
“Off-roading” means you’ve left the
North American road
system behind. Traffic lanes aren’t marked. Curves
aren’t banked. There are no road signs. Surfaces can
be slippery, rough, uphill or downhill. In short, you’ve
gone right back
to nature.
Off-road driving involves some new skills. And that’s
why it’s very important that you read this guide.
You’ll find many driving tips and suggestions. These will
help make your off-road driving safer and more
enjoyable.
4-1 5

Environmental Concerns
Off-road driving can provide wholesome and satisfying
recreation. However, it also raises environmental
concerns. We recognize these concerns and urge every
off-roader to follow these basic rules for protecting
the environment:
e
e
e
e
e
Always use established trails, roads and areas that
have been specially set aside for public off-road
recreational driving; obey all posted regulations.
Avoid any driving practice that could damage the
environment
- shrubs, flowers, trees, grasses -
or disturb wildlife (this includes wheel-spinning,
breaking down trees or unnecessary driving through
streams or over soft ground).
Always carry a liter bag
... make sure all refuse is
removed from any campsite before leaving.
Take extreme care with open fires (where
permitted), camp stoves and lanterns.
Never park your vehicle over dry grass or other
combustible materials that could catch fire form
the heat of the vehicle’s exhaust system.
Traveling to Remote Areas
It makes sense to plan your trip, especially when going
to
a remote area. Know the terrain and plan your
route. You are much less likely to get bad surprises.
Get accurate maps of trails and terrain.
Try to learn of
any blocked or closed roads.
It’s also a good idea to travel with at least one other
vehicle.
If something happens to one of them, the other
can help quickly.
Getting Familiar with Off-Road Driving
It’s a good idea to practice in an area that’s safe
and close to home before you go into the wilderness.
Off- road driving does require some new and different
driving skills. Here’s what we mean.
Tune your senses to different kinds of signals. Your
eyes, for example, need to constantly sweep the terrain
for unexpected obstacles. Your ears need to listen
for unusual tire or engine sounds. With your arms,
hands, feet and body, you’ll need to respond to
vibrations and vehicle bounce.
4-1 7

Driving to the top (crest) of a hill at full speed
can cause an accident. There could be a
drop-off, embankment, cliff, or even another
vehicle. You could be seriously injured or
killed.
As you near the top of a hill, slow down
and stay alert.
Q: What should I do if my vehicle stalls, or is
about to stall, and
I can’t make it up the hill?
A: If this happens, there are some things you should
do, and there are some things you must not do?
First, here’s what you should do:
Push the brake pedal to stop the vehicle and keep
it from rolling backwards. Also, apply the parking
brake.
If your engine is still running, shift the transmission
to REVERSE (R), release the parking brake, and
slowly back down the hill in REVERSE (R).
0 If your engine has stopped running, you’ll need to
restart it. With the brake pedal pressed and the
parking brake still applied, shift the transmission to
PARK (P) and restart the engine. Then shift to REVERSE
(R), release the parking brake, and
slowly back down the hill as straight as possible
in
REVERSE (R).
As you are backing down the hill, put your left hand
on the steering wheel at the
12 o’clock position.
This way you’ll be able to tell
if your wheels
are straight and maneuver as you back down. It’s
best that you back down the hill with your
wheels straight rather than in the left or right
direction. Turning the wheel too far to the left or
right will increase the possibility of a rollover.
Here are some things you
must not do if you stall, or
are about to stall, when going up a hill.
Never attempt to prevent a stall by shifting into
NEUTRAL (N) to “rev-up” the engine and regain
forward momentum. This won’t work. Your vehicle
will roll backwards very quickly and you could
go out of control.
Instead, apply the regular brake to stop the vehicle.
Then apply the parking brake. Shift to
REVERSE (R), release the parking brake, and
slowly back straight down.
0 Never attempt to turn around if you are about to stall
when going up a hill. If the hill is steep enough to stall
your vehicle, it’s steep enough to cause you to roll
over
if you turn around. If you can’t make it up the hill
you must back straight down the hill.
4-21

Q: Suppose, after stalling, I try to back down the
hill and decide
I just can’t do it. What
should
I do?
A: Set the parking brake, put your transmission in
PARK (P) and turn
off the engine. Leave the
vehicle and go get some help. Exit on the uphill
side and stay clear of the path the vehicle would
take
if it rolled downhill.
Driving Downhill
When off-roading takes you downhill, you’ll want to
consider a number of things:
How steep is the downhill? Will I be able to maintain
vehicle control?
What’s the surface like? Smooth? Rough? Slippery?
Are there hidden surface obstacles? Ruts? Logs?
Hard-packed dirt? Gravel?
Boulders?
What’s at the bottom of the hill? Is there a there a
hidden creek bank or even a river bottom with
large rocks?
If you decide you can go down a hill safely, then
try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help your brakes
and they won’t have
to do all the work. Descend slowly,
keeping your vehicle under control at all times.
4-22
Heavy braki.., when going down a hill can
cause your brakes to overheat and fade. This
could cause
loss of control and a serious
accident. Apply the brakes lightly when
descending a hill and use a low gear to keep
vehicle speed under control.
Q: Are there some things I should not do when
driving down
a hill?
A: Yes! These are important because if you ignore
them you could
lose control and have a serious
accident.
When driving downhill, avoid turns that take you
across the incline
of the hill. A hill that’s not too
steep to drive down may be too steep to drive
across. You could roll over
if you don’t drive straight
down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free wheeling”. Your
brakes will have to do all the work and could
overheat and fade.

Q: Am I likely to stall when going downhill?
A: It’s much more likely to happen going uphill. But if it
happens going downhill, here’s what to do.
Apply the parking brake.
engine.
and drive straight down.
Stop your vehicle by applying the regular brakes.
Shift to PARK (P) and, while still braking, restart the
Shift back to a low gear, release the parking brake,
If the engine won’t start, get out and get help.
Driving Across an Incline
Sooner or later, an off-road trail will probably go across
the incline of a hill. If this happens, you have to
decide whether to try to drive across the incline. Here
are some things to consider:
A hill that can be driven straight up or down may be
too steep to drive across. When you go straight up
or down a hill, the length of the wheel base (the distance from
the front wheels to the rear wheels)
reduces the likelihood the vehicle will tumble
end over end. But when you drive across an incline,
the much more narrow track width (the distance
between the left and right wheels) may not prevent
the vehicle from tilting and rolling over.
Also,
driving across an incline puts more weight on the
downhill wheels. This could cause
a downhill
slide or a rollover.
Surface conditions can be a problem when you
drive across a hill. Loose gravel, muddy spots,
or even wet grass can cause your tires to slip
sideways, downhill.
If the vehicle slips sideways, it
can hit something that will trip it (a rock, a rut,
etc.) and roll over.
Hidden obstacles can make the steepness of the
incline even worse.
If you drive across a rock with the
uphill wheels, or it the downhill wheels drop into a rut
or depression, your vehicle can tilt even more.
4-23

Driving in Water
Heavy rain can mean flash flooding, and flood waters
demand extreme caution.
Find out how deep the water is before you drive through
it.
If it’s deep enough to cover your wheel hubs, axles
or exhaust pipe, don’t try
it - you probably won’t
get through. Also, water that deep can damage your
axle and other vehicle parts.
If the water isn’t too deep, drive slowly through it. At
faster speeds, water splashes on your ignition system
and your vehicle can stall. Stalling can also occur
if you
get your tailpipe under water. And, as long as your
tailpipe
is under water, you’ll never be able to start your
engine. When you go through water, remember that
when your brakes get wet, it may take you longer
to stop.
Driving through rushing water can be
dangerous. Deep water can sweep your vehicle
downstream and you and your passengers
CAUTION: (Continued)
1
coula arowr r it’s y snallo‘ Mater, can
still wash away the ground from under your
tires, and you could lose traction and roll the
vehicle over. Don’t drive through rushing
water.
See Driving in Rain and on Wet Roads on page 4-28 for
more information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. Theses substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust
system for damage.
Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service due
to
off-road use. Refer to the Maintenance Schedule
for additional information.
4-26

Hydroplaning C ‘vir T’ lough --
Hydroplaning is dangerous. So much water can build up
under your tires that they can actually ride on the
water. This can happen
if the road is wet enough and
you’re going fast enough. When your vehicle is
hydroplaning, it has little or no contact with the road.
Hydroplaning doesn’t happen often. But it can
if
your tires do not have much tread or if the pressure in
one or more is low.
It can happen if a lot of water is
standing on the road. If you can see reflections
from trees, telephone poles or other vehicles, and
raindrops “dimple” the water’s surface, there could be
hydroplaning.
Hydroplaning usually happens at higher speeds. There
just isn’t
a hard and fast rule about hydroplaning.
The best advice
is to slow down when it is raining.
Driving Through Deep Standing Water
Notice: If you drive too quickly through deep
puddles or standing water, water can come
in
through your engine’s air intake and badly damage
your engine. Never drive through water that is
slightly lower than the underbody of your vehicle.
If
you can’t avoid deep puddles or standing water,
drive through them very slowly.
owing W
-
:er
-
Flowing or rushing water creates strong
forces.
If you try to drive through flowing
water, as you might
at a low water crossing,
your vehicle can be carried away.
As little as
six inches of flowing water can carry away
a
smaller vehicle. If this happens, you and other
vehicle occupants could drown. Don’t ignore police warning signs, and otherwise be very
cautious about trying to drive through flowing
water.
Some Other Rainy Weather Tips
Besides slowing down, allow some extra following
distance. And be especially careful when you
pass another vehicle. Allow yourself more clear
room ahead, and be prepared
to have your
view restricted by road spray.
Have good tires with proper tread depth. See Tires
on page 5-52.
4-30