brake light GMC ACADIA 2008 User Guide

SERVICE AIR BAG
This message displays if there is a problem with the
airbag system. Have your dealer/retailer inspect
the system for problems. SeeAirbag Readiness Light
on page 3-42andAirbag System on page 1-61for
more information.
SERVICE ALL WHEEL DRIVE
If your vehicle has the All-Wheel Drive (AWD) system,
this message displays if there is a problem with this
system. If this message appears, stop as soon as
possible and turn off the vehicle. Restart the vehicle
after 30 seconds and check for the message on the
DIC display. If the message is still displayed or appears
again when you begin driving, the AWD system
needs service. See your dealer/retailer.
SERVICE BATTERY CHARGING
SYSTEM
On some vehicles, this message displays if there is a
problem with the battery charging system. Under certain
conditions, the charging system light may also turn
on in the instrument panel cluster. SeeCharging System
Light on page 3-45. Driving with this problem could
drain the battery. Turn off all unnecessary accessories.
Have the electrical system checked as soon as
possible. See your dealer/retailer.
SERVICE BRAKE SYSTEM
This message displays along with the brake system
warning light if there is a problem with the brake system.
SeeBrake System Warning Light on page 3-47. 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 as soon as possible.
See your dealer/retailer.
SERVICE PARK ASSIST
If your vehicle has the Ultrasonic Rear Parking Assist
(URPA) system, this message displays if there is a
problem with the URPA system. Do not use this
system to help you park. SeeUltrasonic Rear Parking
Assist (URPA) on page 2-45for more information.
See your dealer/retailer for service.
SERVICE POWER STEERING
This message displays when a problem is detected
with the power steering system. When this message
is displayed, you may notice that the effort required to
steer the vehicle increases or feels heavier, but you
will still be able to steer the vehicle. Have your vehicle
serviced by your dealer/retailer immediately.
3-72

Braking
SeeBrake System Warning Light on page 3-47.
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.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 might 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 could 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 can take longer to stop and
the brake pedal will be harder to push.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-4.
4-4

Antilock Brake System (ABS)
Your vehicle has the Antilock Brake System (ABS), an
advanced electronic braking system that will help
prevent a braking skid.
When you start the engine and begin to drive away,
ABS will check itself. You might hear a momentary
motor or clicking noise while this test is going on, and
you might even notice that the brake pedal moves
a little. This is normal.
If there is a problem with
ABS, this warning light will
stay on. SeeAntilock
Brake System Warning
Light on page 3-48.
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 wheel.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, the computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
Remember: ABS does not change the time you need to
get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle in
front of you, you will not have time to apply the brakes if
that vehicle suddenly slows or stops. Always leave
enough room up ahead to stop, even though you
have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down rmly and let antilock work for you. You might hear
the antilock pump or motor operate, and feel the
brake pedal pulsate, but this is normal.
4-5

Braking in Emergencies
With ABS, you can steer and brake at the same time. In
many emergencies, steering can help you more than
even the very best braking.
Panic Brake Assist
Your vehicle has a Panic Brake Assist feature designed
to assist the driver in stopping or decreasing vehicle
speed in emergency driving conditions. This feature uses
the Electronic Stability Control (ESC) hydraulic brake
control module to supplement the power brake system
under conditions where the driver has quickly and
forcefully applied the brake pedal in an attempt to quickly
stop or slow down the vehicle. The ESC hydraulic brake
control module increases brake pressure at each corner
of the vehicle until the Antilock Brake System (ABS)
activates. Minor brake pedal pulsations or pedal
movement during this time is normal and the driver
should continue to apply the brake pedal as the driving
situation dictates. The Panic Brake Assist feature will
automatically disengage when the brake pedal is
released or brake pedal pressure is quickly decreased.
StabiliTrak®System
Your vehicle has the StabiliTrak®system which
combines antilock brake, traction and stability control
systems and helps the driver maintain directional control
of the vehicle in most driving conditions.
When you rst start your vehicle and begin to drive
away, the system performs several diagnostic checks to
ensure there are no problems. You may hear or feel
the system working. This is normal and does not mean
there is a problem with your vehicle. The system
should initialize before the vehicle reaches 20 mph
(32 km/h). In some cases, it may take approximately
two miles of driving before the system initializes.
If the system fails to turn on or activate, the StabiliTrak
®
light along with one of the following messages will be
displayed on the Driver Information Center (DIC):
TRACTION CONTROL OFF, SERVICE TRACTION
CONTROL, SERVICE STABILITRAK. If you see these
conditions, turn the vehicle off, wait 15 seconds, and then
turn it back on again to reset the system. If any of these
messages still appear on the Driver Information Center
(DIC), your vehicle should be taken in for service. For
more information on the DIC messages, seeDriver
Information Center (DIC) on page 3-57.
4-6

The StabiliTrak®light will
ash on the instrument
panel cluster when
the system is both on and
activated.
You may also feel or hear the system working; this is
normal.
The traction control disable
button is located on the
instrument panel below the
climate controls.
The traction control part of StabiliTrak
®can be turned
off by pressing and releasing the traction control disable
button.Traction control can be turned on by pressing and
releasing the traction control disable button if not
automatically shut off for any other reason.
When the traction control system is turned off, the
StabiliTrak
®light and the appropriate traction control off
message will be displayed on the DIC to warn the
driver. Your vehicle will still have brake-traction control
when traction control is off, but will not be able to
use the engine speed management system. See
“Traction Control Operation” next for more information.
When the traction control system has been turned
off, you may still hear system noises as a result of the
brake-traction control coming on.
It is recommended to leave the system on for normal
driving conditions, but it may be necessary to turn
the system off if your vehicle is stuck in sand, mud, ice
or snow, and you want to “rock” your vehicle to
attempt to free it. It may also be necessary to turn off
the system when driving in extreme off-road conditions
where high wheel spin is required. SeeIf Your
Vehicle is Stuck in Sand, Mud, Ice, or Snow on
page 4-20.
4-7

Traction Control Operation
The traction control system is part of the StabiliTrak®
system. Traction control limits wheel spin by reducing
engine power to the wheels (engine speed
management) and by applying brakes to each individual
wheel (brake-traction control) as necessary.
The traction control system is enabled automatically
when you start your vehicle. It will activate and the
StabiliTrak
®light will ash if it senses that any of the
wheels are spinning or beginning to lose traction while
driving. If you turn off traction control, only the
brake-traction control portion of traction control will
work. The engine speed management will be disabled.
In this mode, engine power is not reduced automatically
and the driven wheels can spin more freely. This can
cause the brake-traction control to activate constantly.
Notice:If you allow the wheel(s) of one axle to spin
excessively while the StabiliTrak
®, ABS and brake
warning lights and the SERVICE STABILITRAK
message are displayed, you could damage the
transfer case. The repairs would not be covered by
your warranty. Reduce engine power and do not
spin the wheel(s) excessively while these lights and
this message are displayed.The traction control system may activate on dry or
rough roads or under conditions such as heavy
acceleration while turning or abrupt upshifts/downshifts
of the transmission. When this happens, you may
notice a reduction in acceleration, or may hear a noise
or vibration. This is normal.
If your vehicle is in cruise control when the system
activates, the StabiliTrak
®light will ash and the cruise
control will automatically disengage. When road
conditions allow you to use cruise again, you may
re-engage the cruise control. SeeCruise Control on
page 3-12.
StabiliTrak
®may also turn off automatically if it
determines that a problem exists with the system. If the
problem does not clear itself after restarting the
vehicle, you should see your dealer/retailer for service.
4-8

Driving in Rain and on Wet Roads
Rain and wet roads can reduce vehicle traction
and affect your ability to stop and accelerate. Always
drive slower in these types of driving conditions
and avoid driving through large puddles and
deep-standing or owing water.
{CAUTION:
Wet brakes can cause crashes. They might not
work as well in a quick stop and could cause
pulling to one side. You could lose control of
the vehicle.
After driving through a large puddle of water
or a car/vehicle wash, lightly apply the brake
pedal until the brakes work normally.
Flowing or rushing water creates strong
forces. Driving through owing water could
cause your vehicle to be carried away. If this
happens, you and other vehicle occupants
could drown. Do not ignore police warnings
and be very cautious about trying to drive
through owing water.
Hydroplaning
Hydroplaning is dangerous. Water can build up under
your vehicle’s tires so they actually ride on the
water. This can happen if the road is wet enough and
you are going fast enough. When your vehicle is
hydroplaning, it has little or no contact with the road.
There is no hard and fast rule about hydroplaning. The
best advice is to slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet weather driving tips
include:
Allow extra following distance.
Pass with caution.
Keep windshield wiping equipment in good shape.
Keep the windshield washer uid reservoir lled.
Have good tires with proper tread depth. SeeTires
on page 5-48.
4-14

Trailer Wiring Harness
Your vehicle is equipped with the following wiring
harness for towing a trailer.
Basic Trailer Wiring
If your vehicle is equipped for heavy duty trailering, the
trailer wiring harness, with a seven-pin connector, is
located at the rear of the vehicle and is tied to the
vehicle’s frame. The harness connector can be plugged
into a seven-pin universal heavy-duty trailer connector
available through your dealer/retailer.
The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
Black: Ground
Light Green: Back-up Lamps
Red/Black: Battery Feed
Dark Blue: Trailer Brake**The fuse for this circuit is installed in the underhood
electrical center, but the wires are not connected. They
should be connected by your dealer/retailer or a
qualied service center.
If the back-up lamp circuit is not functional, contact your
dealer/retailer.
If you are charging a remote (non-vehicle) battery, press
the Tow/Haul mode switch located on the center
console near the climate controls. This will boost the
vehicle system voltage and properly charge the battery.
If the trailer is too light for Tow/Haul mode, you can
turn on the headlamps (Non-HID only) as a second way
to boost the vehicle system and charge the battery.
Engine Cooling When Trailer Towing
Your cooling system may temporarily overheat during
severe operating conditions. SeeEngine Overheating on
page 5-25.
4-41

Brakes
Brake Fluid
The brake master cylinder
reservoir is lled with
DOT-3 brake uid. See
Engine Compartment
Overview on page 5-14for
the location of the
reservoir.
There are only two reasons why the brake uid level in
the reservoir might go down. The rst is that the
brake uid goes down to an acceptable level during
normal brake lining wear. When new linings are put in,
the uid level goes back up. The other reason is
that uid is leaking out of the brake hydraulic system. If
it is, you should have the brake hydraulic system
xed, since a leak means that sooner or later the brakes
will not work well.
It is not a good idea to top off the brake uid. Adding
brake uid will not correct a leak. If uid is added when
the linings are worn, there will be too much uidwhen new brake linings are installed. Add or remove
brake uid, as necessary, only when work is done on the
brake hydraulic system.{CAUTION:
If your vehicle has too much brake uid, it can
spill on the engine. The uid will burn if the
engine is hot enough. You or others could be
burned, and your vehicle could be damaged.
Add brake uid only when work is done on the
brake hydraulic system.
When the brake uid falls to a low level, the brake
warning light comes on. SeeBrake System Warning
Light on page 3-47.
What to Add
When you need brake uid, use only DOT-3 brake uid.
Use new brake uid from a sealed container only.
SeeRecommended Fluids and Lubricants on page 6-12.
Always clean the brake uid reservoir cap and the
area around the cap before removing it. This helps keep
dirt from entering the reservoir.
5-35

{CAUTION:
With the wrong kind of uid in the brake
hydraulic system, the brakes might not work
well. This could cause a crash. Always use the
proper brake uid.
Notice:
Using the wrong uid can badly damage brake
hydraulic system parts. For example, just a
few drops of mineral-based oil, such as engine
oil, in the brake hydraulic system can damage
brake hydraulic system parts so badly that they
will have to be replaced. Do not let someone
put in the wrong kind of uid.
If you spill brake uid on your vehicle’s painted
surfaces, the paint nish can be damaged. Be
careful not to spill brake uid on your vehicle. If
you do, wash it off immediately. SeeWashing
Your Vehicle on page 5-92.
Brake Wear
Your vehicle has disc brakes. Disc brake pads have
built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads
are needed. The sound can come and go or be heard all
the time your vehicle is moving, except when you are
pushing on the brake pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon the brakes will not work well. That could
lead to an accident. When you hear the brake
wear warning sound, have your vehicle
serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can cause a brake
squeal when the brakes are rst applied or lightly
applied. This does not mean something is wrong with
the brakes.
5-36