2003 GMC SONOMA tires

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-9
Safety Belts
.............................................1-10
Child Restraints
.......................................1-30
Air Bag System
.......................................1-54
Restraint System Check
............................1-64
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
....................................... 2-8
Windows
.................................................2-14
Theft-Deterrent Systems
............................2-17
Starting and Operating Your Vehicle
...........2-20
Mirrors
....................................................2-39
Storage Areas
.........................................2-41
Sunroof
..................................................2-52
Vehicle Personalization
.............................2-54
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-2
Climate Controls
......................................3-17
Warning Lights, Gages and Indicators
.........3-20
Audio System(s)
.......................................3-36
Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-42Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
................. 5-8
Rear Axle
...............................................5-47
Four-Wheel Drive
.....................................5-48
Front Axle
...............................................5-49
Bulb Replacement
....................................5-50
Windshield Wiper Blade Replacement
.........5-56
Tires
......................................................5-58
Appearance Care
.....................................5-79
Vehicle Identification
.................................5-87
Electrical System
......................................5-88
Capacities and Specifications
.....................5-94
Normal Maintenance Replacement Parts
......5-96
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance Information
.................. 7-2
Reporting Safety Defects
............................ 7-8
Index................................................................ 1
2003 GMC Sonoma Owner ManualM
2003 - Sonoma Owner Manual

The SERVICE ENGINE SOON or CHECK ENGINE light
comes on to indicate that there is a problem and
service is required. Malfunctions often will be indicated
by the system before any problem is apparent. This
may prevent more serious damage to your vehicle. This
system is also designed to assist your service
technician in correctly diagnosing any malfunction.
Notice:If you keep driving your vehicle with this
light on, after a while, your emission controls
may not work as well, your fuel economy may not
be as good and your engine may not run as
smoothly. This could lead to costly repairs that may
not be covered by your warranty.
Notice:Modications made to the engine,
transmission, exhaust, intake or fuel system of your
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modications to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to pass a required Emission
Inspection/Maintenance test.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is not
running. If the light doesn’t come on, have it repaired.This light will also come on during a malfunction in one of
two ways:
Light Flashing—Amisre condition has been
detected. A misre increases vehicle emissions and
may damage the emission control system on your
vehicle. Diagnosis and service may be required.
Light On Steady—An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service may be required.
If the Light Is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
Avoiding steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stopsashing and remains on steady, see
“If the Light Is On Steady”following.
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2003 - Sonoma OM

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.
Avoid needless heavy braking. Some people drive in
spurts—heavy acceleration followed by heavy
braking—rather than keeping pace with traffic.
This is a mistake. Your brakes may not have time to
cool between hard stops. Your brakes will wear
out much faster if you do a lot of heavy braking.
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2003 - Sonoma OM

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.
4-8
2003 - Sonoma OM

Loss of Control
Let’s review what driving experts say about what happens
when the three control systems (brakes, steering and
acceleration) don’t have enough friction where the tires
meet the road to do what the driver has asked.
In any emergency, don’t give up. Keep trying to steer
and constantly seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking reasonable
care suited to existing conditions, and by not
“overdriving”those conditions. But skids are always
possible.
The three types of skids correspond to your vehicle’s
three control systems. In the braking skid, your wheels
aren’t rolling. In the steering or cornering skid, too much
speed or steering in a curve causes tires to slip and lose
cornering force. And in the acceleration skid, too much
throttle causes the driving wheels to spin.
A cornering skid is best handled by easing your foot off
the accelerator pedal.If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want
the vehicle to go. If you start steering quickly enough,
your vehicle may straighten out. Always be ready
for a second skid if it occurs.
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.
4-12
2003 - Sonoma OM

Loading Your Vehicle for Off-Road
Driving
There are some important things to remember about
how to load your vehicle.
The heaviest things should be on the loadoor and
forward of your rear axle. Put heavier items as far
forward as you can.
Be sure the load is secured properly, so driving on
the off-road terrain doesn’t toss things around.
{CAUTION:
•Cargo on the load floor piled higher than
the seatbacks can be thrown forward
during a sudden stop.You or your
passengers could be injured.Keep cargo
below the top of the seatbacks.
CAUTION: (Continued)
CAUTION: (Continued)
•
Unsecured cargo on the load floor can be
tossed about when driving over rough
terrain.You or your passengers can be
struck by flying objects.Secure the cargo
properly.
•Heavy loads on the roof raise the vehicle’s
center of gravity, making it more likely to
roll over.You can be seriously or fatally
injured if the vehicle rolls over.Put heavy
loads inside the cargo area, not on the
roof.Keep cargo in the cargo area as far
forward and low as possible.
You’llnd other important information in this manual.
SeeLoading Your Vehicle on page 4-46,Luggage
Carrier on page 2-50andTires on page 5-58.
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2003 - Sonoma OM

Never go downhill with the transmission in
NEUTRAL (N), or with the clutch pedal pressed
down in a manual shift. 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.
Stop your vehicle by applying the regular brakes.
Apply the parking brake.
Shift to PARK (P) (or to neutral with the manual
transmission) and, while still braking, restart the
engine.
Shift back to a low gear, release the parking brake,
and drive straight down.
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.
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2003 - Sonoma OM

Driving in Mud, Sand, Snow or Ice
When you drive in mud, snow or sand, your wheels
won’t get good traction. You can’t accelerate as quickly,
turning is more difficult, and you’ll need longer braking
distances.
It’s best to use a low gear when you’re in mud—the
deeper the mud, the lower the gear. In really deep mud,
the idea is to keep your vehicle moving so you don’t
get stuck.
When you drive on sand, you’ll sense a change in
wheel traction. But it will depend upon how loosely
packed the sand is. On loosely packed sand (as
on beaches or sand dunes) your tires will tend to sink
into the sand. This has an effect on steering,
accelerating and braking. Drive at a reduced speed
and avoid sharp turns or abrupt maneuvers.Hard packed snow and ice offer the worst tire traction.
On these surfaces, it’s very easy to lose control. On
wet ice, for example, the traction is so poor that you will
have difficulty accelerating. And if you do get moving,
poor steering and difficult braking can cause you to slide
out of control.
{CAUTION:
Driving on frozen lakes, ponds or rivers can be
dangerous.Underwater springs, currents
under the ice, or sudden thaws can weaken the
ice.Your vehicle could fall through the ice and
you and your passengers could drown.Drive
your vehicle on safe surfaces only.
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2003 - Sonoma OM