2004 GMC ENVOY XL brakes

Automatic Transmission Operation
There are several different positions for your gear
shift lever.
PARK (P):This position locks the rear wheels. It’s the
best position to use when you start the engine because
your vehicle can’t move easily.
{CAUTION:
It is dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
Do not leave your vehicle when the engine
is running unless you have to. If you have
left the engine running, the vehicle can move
suddenly. You or others could be injured.
To be sure your vehicle will not move, even
when you are on fairly level ground, always
set your parking brake and move the shift
lever to PARK (P). SeeShifting Into Park (P)
on page 2-31. If you are pulling a trailer, see
Towing a Trailer on page 4-55.
{CAUTION:
If you have four-wheel drive, your vehicle
will be free to roll — even if your shift lever
is in PARK (P) — if your transfer case is in
NEUTRAL. So, be sure the transfer case is in a
drive gear — not in NEUTRAL. SeeFour-Wheel
Drive on page 2-26. SeeShifting Into Park (P)
on page 2-31.
Ensure 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 the
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, press the
button on the shift lever and push the shift lever all the
way into PARK (P) as you maintain brake application.
Move the shift lever into the gear you wish. SeeShifting
Out of Park (P) on page 2-33.
2-24

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 the brakes off and on.
You can also use SECOND (2) for starting the 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 selector lever is put in FIRST (1) while the vehicle
is moving forward, the transmission won’t shift into
rst gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle
in one place on a hill using only the accelerator
pedal may damage the transmission. If you
are stuck, do not spin the tires. When stopping on
a hill, use the brakes to hold the vehicle in place.Four-Wheel Drive
If your vehicle has four-wheel drive, you can send
your engine’s driving power to all four wheels for extra
traction. To get the most satisfaction out of four-wheel
drive, you must be familiar with its operation. Read
the part that follows before using four-wheel drive.
You should use two-wheel drive high (2HI) for most
normal driving conditions.
Notice:Driving on pavement in four-wheel drive
for an extended period of time may cause premature
wear on your vehicle’s powertrain. Do not drive in
four-wheel drive on pavement for extended periods
of time.
Automatic Transfer Case
If your vehicle is equipped
with four-wheel drive,
the transfer case knob is
located to the right of
the steering wheel on the
instrument panel. Use
this knob to shift into and
out of four-wheel drive.
2-26

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 2-24.
Parking Over Things That Burn
{CAUTION:
Things that can burn could touch hot exhaust
parts under your vehicle and ignite. Do not
park over papers, leaves, dry grass or other
things that can burn.
2-33

9(Off):This position turns the cruise control system
off and cancels memory of a set speed.
With cruise control, you can maintain a speed of about
25 mph (40 km/h) or more without keeping your foot
on the accelerator. This can really help on long
trips. Cruise control does not work at speeds below
about 25 mph (40 km/h).
If you apply your brakes, the cruise control will shut off.
{CAUTION:
Cruise control can be dangerous where you
can not drive safely at a steady speed. So, do
not use your cruise control on winding roads
or in heavy traffic.
Cruise control can be dangerous on slippery
roads. On such roads, fast changes in tire
traction can cause needless wheel spinning,
and you could lose control. Do not use cruise
control on slippery roads.
{CAUTION:
If you leave your cruise control on when you
are not using cruise, you might hit a button
and go into cruise when you do not want to.
You could be startled and even lose control.
Keep the cruise control switch off until you
want to use cruise control.
3-13

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. A chime
may also sound when
the light comes on.
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 3-40
earlier in this section.
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 it xed so it will
be ready to warn you if there is a problem.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
If the gage pointer moves into the red area, it means
that your engine coolant has overheated. If you
have been operating your vehicle under normal driving
conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible.
SeeEngine Overheating on page 5-28for more
information.
United StatesCanada
3-42

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 are driving on snow or ice,
it is 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 isperception time.Then you have to bring up your
foot and do it. That isreaction time.
Averagereaction timeis about 3/4 of a second. But that
is 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 is 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.
4-6

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. 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 are driving, brake
normally but do not 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 is a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-42.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there is a DRP problem,
both the brake and ABS warning lights will come on
accompanied by a 10-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.
4-7

Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is 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.The anti-lock system can change the brake pressure
faster than any driver could. The computer is
programmed to make the most of available tire and
road conditions. This can help you steer around
the obstacle while braking hard.
As you brake, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
4-8