2003 GMC SONOMA brakes

Make sure the shift lever is fully in PARK (P) before
starting the engine. Your vehicle has an automatic
transmission shift lock control system. You have to fully
apply your regular brakes before you can shift from
PARK (P) when the ignition key is in RUN. If you cannot
shift out of PARK (P), ease pressure on the shift
lever–push the shift lever all the way into PARK (P) as
you maintain brake application. Then move the shift
lever into the gear you wish. SeeShifting Out of Park (P)
on page 2-35.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your vehicle
is moving forward could damage your transmission.
Shift to REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out of snow,
ice or sand without damaging your transmission,
seeIf You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-40.
NEUTRAL (N):In this position, your engine doesn’t
connect with the wheels. To restart when you’re already
moving, use NEUTRAL (N) only.
{CAUTION:
Shifting into a drive gear while your engine is
“racing”(running at high speed) is dangerous.
Unless your foot isfirmly on the brake pedal,
your vehicle could move very rapidly. You
could lose control and hit people or objects.
Don’t shift into a drive gear while your engine
is racing.
Notice:Damage to your transmission caused by
shifting out of PARK (P) or NEUTRAL (N) with
the engine racing isn’t covered by your warranty.
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2003 - Sonoma OM

DRIVE (D):This position is for normal driving.
If you need more power for passing, and you’re:
•Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
•Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You’ll shift down to the next gear and have more power.
DRIVE (D) should not be used when towing a trailer,
carrying a heavy load, driving on steep hills, or for
off-road driving. Select THIRD (3) when operating the
vehicle under any of these conditions.
THIRD (3):This position is also used for normal driving,
however, it offers more power and lower fuel economy
than DRIVE (D). You should use THIRD (3) when towing
a trailer, carrying a heavy load, driving on steep hills
or winding roads or for off-road driving.
SECOND (2):This position gives you more power but
lower fuel economy than THIRD (3). You can use
SECOND (2) on hills. It can help control your speed as
you go down steep mountain roads, but then you
would also want to use your brakes off and on. You can
also use SECOND (2) for starting your vehicle from a
stop on slippery road surfaces.FIRST (1):This position gives you even more power
but lower fuel economy than SECOND (2). You can use
it on very steep hills, or in deep snow or mud. If the
shift lever is put in FIRST (1) while the vehicle is moving
forward, the transmission won’t shift into FIRST (1)
until the vehicle is going slowly enough.
Notice:If your wheels won’t turn, don’t try to drive.
This might happen if you were stuck in very deep
sand or mud or were up against a solid object. You
could damage your transmission. Also, if you
stop when going uphill, don’t hold your vehicle there
with only the accelerator pedal. This could overheat
and damage the transmission. Use your brakes
or shift into PARK (P) to hold your vehicle in
position on a hill.
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2003 - Sonoma OM

Parking Brake
The parking brake is located near the bottom of the
instrument panel on the driver’s side of the vehicle.
To set the parking brake, hold the regular brake pedal
down with your right foot. Push down the parking
brake pedal with your left foot. If the ignition is on, the
brake system warning light will come on.
Notice:Driving with the parking brake on can
cause your rear brakes to overheat. You may have
to replace them, and you could also damage
other parts of your vehicle.
To release the parking brake, hold the regular brake
pedal down. Pull the BRAKE RELEASE lever fully.
It is located on the bottom off the instrument panel on
the driver’s side of the vehicle.If you are towing a trailer and you must park on a hill,
seeTowing a Trailer on page 4-51. That section
shows what to dofirst to keep the trailer from moving.
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2003 - Sonoma OM

Torque Lock
If you are parking on a hill and you don’t shift your
transmission into PARK (P) properly, the weight of the
vehicle may put too much force on the parking pawl in the
transmission. You mayfind it difficult to pull the shift lever
out of PARK (P). This is called“torque lock”To prevent
torque lock, set the parking brake and then shift into
PARK (P) properly before you leave the driver’s seat.
Tofind out how, seeShifting Into Park (P) on page 2-33.
When you are ready to drive, move the shift lever out of
PARK (P) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission,
so you can pull the shift lever out of PARK (P).
Shifting Out of Park (P)
Your vehicle has an automatic transmission shift lock
control system. You have to fully apply the regular
brakes before you can shift from PARK (P) when the
ignition is in RUN. SeeAutomatic Transmission
Operation on page 2-25.
If you cannot shift out of PARK (P), ease pressure on
the shift lever–push the shift lever all the way into
PARK (P) as you maintain brake application. Then move
the shift lever into the gear you want. You must press
the shift lever button on the shift lever.
If you ever hold the brake pedal down but still can’t shift
out of PARK (P), try this:
1. Turn the key to OFF.
2. Apply and hold the brake until the end of Step 4.
3. Shift the transmission to NEUTRAL (N).
4. Start the vehicle and then shift to the drive gear
you want.
5. Have the vehiclefixed as soon as possible.
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2003 - Sonoma OM

Passing Another Vehicle While Using
Cruise Control
Use the accelerator pedal to increase your speed.
When you take your foot off the pedal, your vehicle will
slow down to the cruise control speed you set earlier.
Using Cruise Control on Hills
How well your cruise control will work on hills depends
upon your speed, load and the steepness of the
hills. When going up steep hills, you may want to step
on the accelerator pedal to maintain your speed.
When going downhill, you may have to brake or shift to
a lower gear to keep your speed down. Of course,
applying the brake takes you out of cruise control. Many
driversnd this to be too much trouble and don’t use
cruise control on steep hills.
Ending Cruise Control
There are two ways to turn off the cruise control:
Step lightly on the brake pedal or push the clutch
pedal, if you have a manual transmission.
If you have an automatic transmission and you
apply your brakes, the cruise control will shut off.
Move the cruise switch to OFF.
Erasing Speed Memory
When you turn off the cruise control or the ignition, your
cruise control set speed memory is erased.
Exterior Lamps
The control on the driver’s side of the instrument panel
operates the exterior lamps.
The exterior lamp control has three positions:
9(Off):Turn the exterior lamps control all the way
counterclockwise to turn off the lamps and put the
system in automatic headlamp mode.
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2003 - Sonoma OM

If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the
oor. It may take longer to stop. If the light is still on,
have the vehicle towed for service. SeeTowing
Your Vehicle on page 4-42.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light is
on. Driving with the brake system warning light
on can lead to an accident. If the light is still
on after you’ve pulled off the road and stopped
carefully, have the vehicle towed for service.
Anti-Lock Brake System Warning
Light
With the anti-lock brake
system, this light will
come on when you start
your engine and may
stay on for several
seconds. That’s normal.
If the light stays on, or comes on when you’re driving,
your vehicle needs service. If the regular brake
system warning light isn’t on, you still have brakes, but
you don’t have anti-lock brakes. If the regular brake
system warning light is also on, you don’t have anti-lock
brakes and there’s a problem with your regular
brakes. SeeBrake System Warning Light on page 3-27.
The anti-lock brake system warning light should come
on briey when you turn the ignition key to RUN. If
the light doesn’t come on then, have itxed so it will be
ready to warn you if there is a problem.
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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

If you keep pace with the traffic and allow realistic
following distances, you will eliminate a lot of
unnecessary braking. That means better braking and
longer brake life.
If your engine ever stops while you’re driving, brake
normally but don’t pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
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. SeeAnti-Lock
Brake System Warning
Light on page 3-28.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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2003 - Sonoma OM