brakes GMC ENVOY 2007 Owner's Manual

{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 122. SeeShifting Into Park (P) on
page 127.
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 the regular brakes rst and
then press the shift lever button 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 and push the shift
lever all the way into PARK (P) as you maintain
brake application. Then press the shift lever button
and move the shift lever into another gear. See
Shifting Out of Park (P) on page 129.
REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your
vehicle is moving forward could damage the
transmission. The repairs would not be covered
by your warranty. 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 Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow on page 348.
119

NEUTRAL (N):In this position, the engine does
not connect with the wheels. To restart when
you are already moving, use NEUTRAL (N) only.
{CAUTION:
Shifting into a drive gear while your
engine is running at high speed is
dangerous. Unless your foot is rmly on
the brake pedal, your vehicle could move
very rapidly. You could lose control and
hit people or objects. Do not shift into a
drive gear while your engine is running at
high speed.
Notice:Shifting out of PARK (P) or
NEUTRAL (N) with the engine running at high
speed may damage the transmission. The
repairs would not be covered by your warranty.
Be sure the engine is not running at high
speed when shifting your vehicle.DRIVE (D):This position is for normal driving.
It provides the best fuel economy for your vehicle.
If you need more power for passing, and you are:
Going less than about 35 mph (55 km/h), push
the accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push
the accelerator all the way down.
You will shift down to the next gear and have
more power.
Downshifting the transmission in slippery road
conditions could result in skidding, see “Skidding”
underLoss of Control on page 318.
DRIVE (D) can be used when towing a trailer,
carrying a heavy load, driving on steep hills, or
for off-road driving. You may want to shift the
transmission to THIRD (3) or, if necessary, a lower
gear selection if the transmission shifts too often.
THIRD (3):This position is also used for normal
driving. It reduces vehicle speed more than
DRIVE (D) without using your brakes. You might
choose THIRD (3) instead of DRIVE (D) when
driving on hilly, winding roads, when towing
a trailer, so there is less shifting between gears
and when going down a steep hill.
120

To shift to the THIRD (3) position, you must rst
press the large button on the shift handle.
While the button is pressed, move the shifter in
the THIRD (3) position.
SECOND (2):This position reduces vehicle speed
even more than THIRD (3) without using your
brakes. 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.
To shift to the SECOND (2) position, you must rst
press the large button on the shift handle. While
the button is pressed, move the shifter in the
SECOND (2) position.
You can also use SECOND (2) for starting the
vehicle from a stop on slippery road surfaces.FIRST (1):This position reduces vehicle speed
even more than SECOND (2) without using
your brakes. 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 will not shift into rst gear until the
vehicle is going slowly enough.
To shift to the FIRST (1) position, you must rst
press the large button on the shift handle.
While the button is pressed, move the shifter in
the FIRST (1) position.
Notice:Spinning the tires or holding the
vehicle in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be covered by
your warranty. If you are stuck, do not spin
the tires. When stopping on a hill, use the
brakes to hold the vehicle in place.
121

Torque Lock
If you are parking on a hill and you do not 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
may nd 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. To nd out how, see
Shifting Into Park (P) on page 127.
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 rst and then press the shift
lever button before you can shift from PARK (P)
when the ignition is in RUN. SeeAutomatic
Transmission Operation on page 118.
129

Cruise Control
Your vehicle has cruise
control. The controls are
located on the end of
the turn signal/
multifunction lever.
R(On):Move the switch to this position to turn
the cruise control system on.
S(Resume/Accelerate):Move the switch to this
position to resume a set speed or to accelerate.
T(Set):Press this button, located at the end of
the lever, to set a speed.
9(Off):Move the switch to this position to turn
the cruise control system off and cancel 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 the brakes, the cruise control shuts off.
{CAUTION:
Cruise control can be dangerous where
you cannot 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
excessive wheel slip, and you could lose
control. Do not use cruise control on
slippery roads.
176

{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.
Setting Cruise Control
1. Move the cruise control switch to on.
2. Get up to the speed you want.
3. Press the set button at the end of the lever
and release it.
4. Take your foot off the accelerator pedal.
The accelerator pedal will not go down.Some vehicles have a
cruise light on the
instrument panel cluster
that will come on
when the cruise control
is engaged.
Resuming a Set Speed
Suppose you set your cruise control at a desired
speed and then you apply the brake. This, of
course, shuts off the cruise control. But you do not
need to reset it.
Once you are going about 25 mph (40 km/h) or
more, you can move the cruise control switch
briey from on to resume/accelerate.
You will go right back up to the previously chosen
speed and stay there.
If you hold the switch at resume/accelerate, the
vehicle keeps going faster until you release
the switch or apply the brakes. So unless you
want to go faster, do not hold the switch at
resume/accelerate.
177

{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 have 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 (ABS),
this light will come
on when you start your
engine and may
stay on for several
seconds, that is normal.
A chime may also sound when the light comes on.If the light stays on, or comes on when you are
driving, your vehicle needs service. If the regular
brake system warning light is not on, you still have
brakes, but you do not have anti-lock brakes. If the
regular brake system warning light is also on, you
do not have anti-lock brakes and there is a problem
with your regular brakes. SeeBrake System
Warning Light on page 206earlier in this section.
The ABS warning light should come on briey
when you turn the ignition key to RUN. If the light
does not come on then, have it xed so it will
be ready to warn you if there is a problem.
StabiliTrak®Service Light
This light will come on
briey when the engine
is started.
This light will come on if a problem is detected in
the StabiliTrak
®system.
For more information seeStabiliTrak
®System on
page 309.
207

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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 380.
Braking
SeeBrake System Warning Light on page 206.
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake
pedal. That is perception time. Then you have to
bring up your foot and do it. That is reaction time.
Average reaction time is about three-fourths 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
three-fourths 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,
whether it is wet, dry, or icy; tire tread; the
condition of the brakes; the weight of the vehicle;
and the amount of brake force applied.
306

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. The brakes may not have time to
cool between hard stops. The 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 vehicle’s engine ever stops while you are
driving, brake normally but do not pump the
brakes. If you do, the pedal may get harder to
push down. If the 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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 380.Anti-Lock Brake System (ABS)
Your vehicle has the Anti-Lock Brake System
(ABS), an advanced electronic braking system that
will help prevent a braking skid.
When you start your engine and begin to drive
away, ABS 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 ABS, this warning
light will stay on.
SeeAnti-Lock Brake
System Warning
Light on page 207.
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.
307

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.ABS 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.
308