2003 GMC SIERRA steering

Control of a Vehicle
You have three systems that make your vehicle go
where you want it to go. They are the brakes, the
steering and the accelerator. All three systems have to
do their work at the places where the tires meet
the road.
Sometimes, as when you’re driving on snow or ice, it’s
easy to ask more of those control systems than the
tires and road can provide. That means you can lose
control of your vehicle.
Braking
Braking action involvesperception timeand
reaction time.
First, you have to decide to push on the brake pedal.
That’sperception time.Then you have to bring up your
foot and do it. That’sreaction time.
Averagereaction timeis about 3/4 of a second.
But that’s only an average. It might be less with one
driver and as long as two or three seconds or more with
another. Age, physical condition, alertness, coordination
and eyesight all play a part. So do alcohol, drugs
and frustration. But even in 3/4 of a second, a vehicle
moving at 60 mph (100 km/h) travels 66 feet (20 m).
That could be a lot of distance in an emergency,
so keeping enough space between your vehicle and
others is important.
And, of course, actual stopping distances vary greatly
with the surface of the road (whether it’s pavement
or gravel); the condition of the road (wet, dry, icy); tire
tread; the condition of your brakes; the weight of
the vehicle and the amount of brake force applied.
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2003 - Sierra Denali

Remember: Anti-lock doesn’t change the time you need
to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to the
vehicle in front of you, you won’t have time to apply
your brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Don’t pump the brakes. Just hold the brake pedal down
rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise, but
this is normal.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
Supplemental Brake Assist System
If your vehicle has vacuum assist power brakes, it is also
equipped with a supplemental brake assist system
that supplies additional vacuum to the vacuum brake
booster if engine vacuum is reduced. Under certain
conditions, the supplemental brake assist system may
run briey after starting your vehicle or when you
apply and release the brake pedal and it may continueto run even after you have removed your foot from the
brake pedal. When the supplemental brake assist
system is operating, you may hear a motor running or
feel a slight vibration in the steering wheel or brake
pedal. This indicates that the supplemental brake assist
system is working to supply additional vacuum for
your vacuum assist power brakes. This is a normal
operation of your brake system and does not require that
the brake system be serviced.
Each time you start your vehicle and accelerate to
10 mph, the supplemental brake assist system
will perform a self-diagnostic check of the system and
you may hear or feel the supplemental brake assist
motor run briey. While you are driving your vehicle, the
supplemental brake assist system monitors itself to
ensure that it is operating properly. If there is a problem
with the supplemental brake assist system, the
SERVICE BRAKE BOOSTER message will be displayed
on the Driver Information Center. SeeDIC Warnings
and Messages on page 3-51.
If your supplemental brake assist system runs every
time you apply and release the brake pedal or you notice
that the brake pedal has suddenly become much
harder to push and the vehicle takes longer to stop, you
should have your vehicle serviced as soon as possible.
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2003 - Sierra Denali

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.
Steering Tips
Driving on Curves
It’s important to take curves at a reasonable speed.
A lot of the“driver lost control”accidents mentioned on
the news happen on curves. Here’s why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves.
The traction of the tires against the road surface makes
it possible for the vehicle to change its path when
you turn the front wheels. If there’s no traction, inertia
will keep the vehicle going in the same direction.
If you’ve ever tried to steer a vehicle on wet ice, you’ll
understand this.The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle at
which the curve is banked, and your speed. While
you’re in a curve, speed is the one factor you can
control.
Suppose you’re steering through a sharp curve.
Then you suddenly accelerate. Both control
systems—steering and acceleration—have to do their
work where the tires meet the road. Adding the
sudden acceleration can demand too much of those
places. You can lose control.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds
are based on good weather and road conditions. Under
less favorable conditions you’ll want to go slower.
If you need to reduce your speed as you approach a
curve, do it before you enter the curve, while your front
wheels are straight ahead.
Try to adjust your speed so you can“drive”through the
curve. Maintain a reasonable, steady speed. Wait to
accelerate until you are out of the curve, and then
accelerate gently into the straightaway.
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Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill andnd
a truck stopped in your lane, or a car suddenly pulls
out from nowhere, or a child darts out from between
parked cars and stops right in front of you. You
can avoid these problems by braking—if you can stop
in time. But sometimes you can’t; there isn’t room.
That’s the time for evasive action—steering around the
problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
SeeBraking on page 4-5. It is better to remove as much
speed as you can from a possible collision. Then
steer around the problem, to the left or right depending
on the space available.An emergency like this requires close attention and a
quick decision. If you are holding the steering wheel at
the recommended 9 and 3 o’clock positions, you
can turn it a full 180 degrees very quickly without
removing either hand. But you have to act fast, steer
quickly, and just as quickly straighten the wheel
once you have avoided the object.
The fact that such emergency situations are always
possible is a good reason to practice defensive driving
at all times and wear safety belts properly.
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2003 - Sierra Denali

QUADRASTEER™
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 4 Wheel Steer
system it has the ability to steer the vehicle with all four
wheels.
Once the 4 Wheel Steer mode is selected, it is
recommended to leave the vehicle in this mode at all
times, and during all driving and weather conditions.
You can select this mode at any speed, however, if you
are turning the system will not engage until the turn
is complete.
The 4 Wheel Steer system is equipped with three
different driving modes:
Two wheel steering (2)
Four wheel steering (4)
Four wheel steering with a trailer mode (_)The switch is located on the instrument panel.
2:In this mode the vehicle will operate like any other
vehicle with two wheel steering. If you want to use
2 wheel steering and your vehicle is not in this mode,
press the button until the 2 indicator, located to the right
of the 4 Wheel Steer button, lights up. If the 2 indicator
isashing you will have to center the steering wheel
by turning it to the left or right.
Your vehicle will return to 2 (two wheel steering) when
the transmission is shifted into NEUTRAL, for
example when entering a car wash.
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4:In this mode all four wheels will help steer the
vehicle. If you want to use 4 wheel steering, and your
vehicle is not in this mode, press the button, until
the 4 indicator, located to the right of the 4 Wheel Steer
button, lights up. If the 4 indicator isashing you will
have to center the steering wheel by turning it to the left
or right.
At slower speeds 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.At higher speeds the front and rear wheels will turn in
the same direction. This improves stability of the vehicle
during lane changes and sweeping turns.
_(4 Wheel Steer tow mode):When towing a
trailer the 4 wheel steer 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 4 mode,
but is enhanced for trailer towing. It is recommended
for all types and weights of trailers. Slower Speeds (below 40 m.p.h./64 km/h)
Higher Speeds (40 m.p.h./64 km/h and above)
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To engage the 4 wheel steer tow mode, press the
4 Wheel Steer button until the 4 and tow indicators light
up on the instrument panel. If the tow indicator is
ashing you will have to center the steering wheel by
turning it to the left or right. While in the 4 wheel
steer tow mode, it is possible the steering wheel may be
slightly off center. For more information, seeTowing a
Trailer on page 4-53.
Car Washes for
QUADRASTEER™ Equipped Vehicles
Notice:Because your vehicle has a wider rear track
a small number of older car washes may be too
narrow for your vehicle.Conveyor systems on some
automatic car washes may damage your vehicle.
Only use conveyor system car washes with 13-inch
(33 cm) wide conveyor rails and/or stationary
washes with at least 82 inches (208 cm) between the
rails.Before using the car wash check with the
manager.
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2003 - Sierra Denali

Off-Road Recovery
You maynd that your right wheels have dropped off
the edge of a road onto the shoulder while you’re
driving.
If the level of the shoulder is only slightly below the
pavement, recovery should be fairly easy. Ease off the
accelerator and then, if there is nothing in the way,
steer so that your vehicle straddles the edge of
the pavement. You can turn the steering wheel up to
one-quarter turn until the right front tire contacts
the pavement edge. Then turn your steering wheel to go
straight down the roadway.
Passing
The driver of a vehicle about to pass another on a
two-lane highway waits for just the right moment,
accelerates, moves around the vehicle ahead, then
goes back into the right lane again. A simple maneuver?
Not necessarily! Passing another vehicle on a two-lane
highway is a potentially dangerous move, since the
passing vehicle occupies the same lane as oncoming
traffic for several seconds. A miscalculation, an error in
judgment, or a brief surrender to frustration or anger
can suddenly put the passing driver face to face with the
worst of all traffic accidents—the head-on collision.
So here are some tips for passing:
“Drive ahead.”Look down the road, to the sides
and to crossroads for situations that might affect
your passing patterns. If you have any doubt
whatsoever about making a successful pass, wait
for a better time.
Watch for traffic signs, pavement markings and
lines. If you can see a sign up ahead that might
indicate a turn or an intersection, delay your pass.
A broken center line usually indicates it’s all
right to pass (providing the road ahead is clear).
Never cross a solid line on your side of the lane or
a double solid line, even if the road seems empty
of approaching traffic.
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