2003 GMC ENVOY Brake system

Cruise Control
The cruise 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):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't drive safely at a steady speed.
So, don't 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. Don't use cruise control on
slippery roads.
3-12

There is a delay in the transition between the daytime
and nighttime operation of the Daytime Running
Lamps (DRL) and the automatic headlamp systems, so
that driving under bridges or bright overhead street
lights does not affect the system. The DRL and
automatic headlamp system will only be affected when
the light sensor sees a change in lighting lasting
longer than the delay.
If you start your vehicle in a dark garage, the automatic
headlamp system will come on immediately. Once
you leave the garage, it will take about one minute for
the automatic headlamp system to change to DRL if it is
light outside. During that delay, your instrument panel
cluster may not be as bright as usual. Make sure
your instrument panel brightness control is in the full
bright position.
To idle your vehicle with the automatic headlamp
system off, set the parking brake while the ignition is off.
Then start your vehicle. The automatic headlamp
system will stay off until you release the parking brake,
shift out of park or turn the exterior lamp control to
the off position as described in ªExterior Lampsº listed
previously.
Lamps On Reminder
A reminder tone will sound when your headlamps or
parking lamps are manually turned on, the driver's door
is open and your ignition is in LOCK or ACCESSORY.To turn the tone off, turn the knob all the way
counterclockwise. In the automatic mode, the headlamps
turn off once the ignition key is in LOCK.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the
day. DRL can be helpful in many different driving
conditions, but they can be especially helpful in the short
periods after dawn and before sunset. Fully functional
daytime running lamps are required on all vehicles
®rst sold in Canada.
The DRL system will make your headlamps come on
at reduced brightness when the following conditions
are met:
·The ignition is on,
·the exterior lamps knob is in automatic headlamp
mode,
·the light sensor detects daytime light, and
·the transmission is not in PARK (P).
When the DRL are on, only your headlamps will be on.
The taillamps, sidemarker and other lamps won't be
on. The instrument panel won't be lit up either.
When it begins to get dark, the headlamps will
automatically switch from DRL to the regular headlamps.
3-16

Voltmeter Gage
When your engine is not
running, but the ignition is
on (in RUN), this gage
shows your battery's state
of charge in DC volts.
When the engine is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left idling for an
extended period. This condition is normal since the
charging system is not able to provide full power
at engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.You can only drive for a short time with the reading in
either warning zone. If you must drive, turn off all
unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Brake System Warning Light
When the ignition is on, the brake system warning light
will come on when you set your parking brake. The
light will stay on if your parking brake doesn't release
fully. If it stays on after your parking brake is fully
released, it means you have a brake problem. A chime
may also sound when the light comes on.
Your vehicle's hydraulic brake system is divided into two
parts. If one part isn't working, the other part can still
work and stop you. For good braking, though, you need
both parts working well.
3-39

If the warning light comes on, there could be a brake
problem. Have your brake system inspected right away.
This light should come on brie¯y when you turn the
ignition key to RUN. If it doesn't come on then, have it
®xed so it will be ready to warn you if there's a
problem.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. See
Towing
Your Vehicle on page 4-45.
{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. United StatesCanada
3-40

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. See
Brake System Warning Light on page 3-39earlier in this section.
The anti-lock brake system warning light should come
on brie¯y 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.
See
Engine Overheating on page 5-27for more
information.
United StatesCanada
3-41

SERVICE BRAKE SYSTEM
If a problem occurs with the brake system this message
will appear on the DIC. If this message appears, stop
as soon as possible and turn off the vehicle. Restart the
vehicle and check for the message on the DIC display.
If the message is still displayed, or appears again when
you begin driving, the brake system needs service.
TURN SIGNAL ON
If a turn signal is left on for 3/4 of a mile (1.2 km), this
message will appear on the display and you will
hear a chime. Move the turn signal/multifunction lever to
the off position. Pressing the select button will
acknowledge this message and clear it from the DIC
display.
REAR ACCESS OPEN
If the liftgate or liftglass is open while the ignition is in
RUN, this message will appear on the DIC and you will
hear a chime. Turn off the vehicle and check the
liftgate and liftglass. Restart the vehicle and check for
the message on the DIC display. Pressing the select
button will acknowledge this message and clear it from
the DIC display.
FUEL LEVEL LOW
If the fuel level is low in the vehicle's gas tank this
message will appear on the DIC and you will hear a
chime. Refuel as soon as possible. Pressing the select
button will acknowledge this message and clear it
from the DIC display.
CHECK WASHER FLUID
If the washer ¯uid level is low, this message will appear
on the DIC. Adding washer ¯uid will clear the message.
Pressing the select button will acknowledge this
message and clear it from the DIC display.
TRANS HOT IDLE ENGINE
If the transmission ¯uid in the vehicle gets hot, this
message will appear on the DIC. Driving with the
transmission ¯uid temperature high can cause damage
to the vehicle. Stop the vehicle and let it idle to allow
the transmission to cool. This message will clear when
the ¯uid temperature reaches a safe level.
3-61

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 timeandreaction 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.
4-5

Avoid needless heavy braking. Some people drive
in spurts Ð heavy acceleration followed by heavy
braking Ð 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'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. See
Anti-Lock
Brake System Warning
Light on page 3-41
.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there's 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.
4-6