2009 GMC YUKON brake light

If the warning light comes on and a chime sounds there
could be a brake problem. Have the brake system
inspected right away.
This light can also come on due to low brake uid. See
Brakes on page 5-41for more information.
This light comes on briey when the ignition key is
turned to ON/RUN. If it does not come on then, have it
xed so it is ready to warn if there is a problem.
{CAUTION:
The brake system might not be working properly if
the brake system warning light is on. Driving with
the brake system warning light on can lead to a
crash. If the light is still on after the vehicle has
been pulled off the road and carefully stopped,
have the vehicle towed for service.
If the light comes on while driving, pull off the road and
stop carefully. The pedal might be harder to push or
might go closer to the oor. It can take longer to stop.
If the light is still on, have the vehicle towed for service.
SeeTowing Your Vehicle on page 4-44. United States
Canada
3-41

Antilock Brake System (ABS)
Warning Light
For vehicles with the
Antilock Brake System
(ABS), this light comes on
briey when the engine
is started.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light then goes off.
If the ABS light stays on, turn the ignition off. If the light
comes on while driving, stop as soon as it is safely
possible and turn the ignition off. Then start the engine
again to reset the system. If the ABS light stays on, or
comes on again while driving, the vehicle needs service.
If the regular brake system warning light is not on, the
vehicle still has brakes, but not antilock brakes. If the
regular brake system warning light is also on, the vehicle
does not have antilock brakes and there is a problem with
the regular brakes. SeeBrake System Warning Light on
page 3-40.
For vehicles with a Driver Information Center (DIC), see
DIC Warnings and Messages on page 3-64for all
brake related DIC messages.
StabiliTrak®Indicator Light
For vehicles with the
StabiliTrak®system, this
light comes on briey while
starting the engine.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light then goes off.
If the light comes on and stays on while driving, there
could be a problem with the StabiliTrak
®system and the
vehicle might need service. When this warning light is
on, the StabiliTrak
®system is off and does not limit
wheel spin.
The light ashes if the system is active and is working
to assist the driver with directional control of the
vehicle in difficult driving conditions.
SeeStabiliTrak
®System on page 4-6for more
information.
3-42

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 3-37andAirbag System on page 1-81for more
information.
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 3-39. 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 3-40. 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 BRAKES SOON
This message displays if there is a problem with the
brake system. 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. 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 2-53for more information. See your
dealer/retailer for service.
SERVICE SIDE BLIND ZONE ALERT
SYSTEM
If your vehicle has the Side Blind Zone Alert (SBZA)
system and this message displays, both SBZA displays
will remain on indicating there is a problem with the
SBZA system. If these displays remain on after
continued driving, the system needs service. See your
dealer/retailer. SeeSide Blind Zone Alert (SBZA)
on page 2-56for more information.
3-69

SERVICE TRAILER BRAKE SYSTEM
On vehicles with the Integrated Trailer Brake Control
(ITBC) system, this message displays and a chime
sounds when there is a problem with the ITBC system.
When this message displays, power is no longer
available to the trailer brakes.
As soon as it is safe to do so, carefully pull your vehicle
over to the side of the road and turn the ignition off.
Check the wiring connection to the trailer and turn the
ignition back on. If this message still displays, either your
vehicle or the trailer needs service. See your
dealer/retailer.
See “Integrated Trailer Brake Control System” under
Towing a Trailer on page 4-52for more information.
SIDE BLIND ZONE ALERT SYSTEM OFF
If your vehicle has the Side Blind Zone Alert (SBZA)
system, this message displays when the SBZA system
has been turned off. SeeSide Blind Zone Alert (SBZA) on
page 2-56andDIC Operation and Displays (With DIC
Buttons) on page 3-52orDIC Operation and Displays
(Without DIC Buttons) on page 3-57for more information.
SIDE BLIND ZONE SYS. (System)
UNAVAILABLE
If your vehicle has the Side Blind Zone Alert (SBZA)
system, this message displays when the SBZA system
is disabled because the sensor is blocked and cannot
detect vehicles in your blind zone. The sensor may
be blocked by mud, dirt, snow, ice, or slush. This
message may also display during heavy rain or due to
road spray. It may also come on when driving in
isolated areas with no guardrails, trees, or road signs
and light traffic. Your vehicle does not need service. For
cleaning instructions, seeWashing Your Vehicle on
page 5-111. SeeSide Blind Zone Alert (SBZA) on
page 2-56for more information.
STABILITRAK OFF
If your vehicle has StabiliTrak, this message displays
when you turn off StabiliTrak, or when the stability control
has been automatically disabled. To limit wheel spin and
realize the full benets of the stability enhancement
system, you should normally leave StabiliTrak on.
However, you should turn StabiliTrak off if your vehicle
gets stuck in sand, mud, ice, or snow and you want to
rock your vehicle to attempt to free it, or if you are driving
in extreme off-road conditions and require more wheel
spin. SeeIf Your Vehicle is Stuck in Sand, Mud, Ice, or
Snow on page 4-31. To turn the StabiliTrak system on or
off, seeStabiliTrak
®System on page 4-6.
3-71

There are several conditions that can cause this
message to appear.
One condition is overheating, which could occur if
StabiliTrak activates continuously for an extended
period of time.
The message also displays if the brake system
warning light is on. SeeBrake System Warning
Light on page 3-40.
The message could display if the stability system
takes longer than usual to complete its diagnostic
checks due to driving conditions.
The message displays if an engine or vehicle
related problem has been detected and the vehicle
needs service. See your dealer/retailer.
The message also displays if the vehicle is shifted
into 4LO.
The message turns off as soon as the conditions that
caused the message to be displayed are no longer
present.
TIGHTEN GAS CAP
This message may display along with the check engine
light on the instrument panel cluster if the vehicle’s
fuel cap is not tightened properly. SeeMalfunction
Indicator Lamp on page 3-44. Reinstall the fuel cap fully.
SeeFilling the Tank on page 5-9. The diagnostic
system can determine if the fuel cap has been left off or
improperly installed. A loose or missing fuel cap
allows fuel to evaporate into the atmosphere. A few
driving trips with the cap properly installed should turn
this light and message off.
TIRE LEARNING ACTIVE
On vehicles with the Tire Pressure Monitor System
(TPMS), this message displays when the TPMS
is re-learning the tire positions on your vehicle. The tire
positions must be re-learned after rotating the tires
or after replacing a tire or sensor. SeeTire Inspection
and Rotation on page 5-78,Tire Pressure Monitor
System on page 5-72, andInflation - Tire Pressure on
page 5-70for more information.
3-72

Braking
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
SeeBrake System Warning Light on page 3-40.
Braking action involves perception time and reaction
time. Deciding to push the brake pedal is perception
time. Actually doing it 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
the 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 with a lot of heavy braking. Keeping pace
with the traffic and allowing realistic following distances
eliminates a lot of unnecessary braking. That means
better braking and longer brake life.
If the engine ever stops while the vehicle is being
driven, brake normally but do not pump the brakes.
If the brakes are pumped, the pedal could get harder
to push down. If the engine stops, there will still be some
power brake assist but it will be used when the brake
is applied. 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
vehicle performance. SeeAccessories and Modifications
on page 5-3.
4-4

Antilock Brake System (ABS)
This vehicle has the Antilock Brake System (ABS), an
advanced electronic braking system that will help
prevent a braking skid.
When the engine is started and the vehicle begins to
drive away, ABS checks itself. A momentary motor
or clicking noise might be heard while this test is going
on. This is normal.
If there is a problem with
ABS, this warning light
stays on. SeeAntilock
Brake System (ABS)
Warning Light on
page 3-42.
Along with ABS, the vehicle has a Dynamic Rear
Proportioning (DRP) system. If there is a DRP problem,
both the brake and ABS warning lights 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/retailer for
service.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 the 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 to each wheel, as
required, faster than any driver could. This can help
the driver steer around the obstacle while braking hard.
As the brakes are applied, the computer keeps receiving
updates on wheel speed and controls braking pressure
accordingly.
Remember: ABS does not change the time needed to
get a foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle in
front of you, there will not be enough time to apply
the brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
with ABS.
4-5

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, STABILITRAK OFF, SERVICE
STABILITRAK. If these DIC messages appear, make
sure the StabiliTrak system has not been turned
off using the StabiliTrak on/off button. Then turn
the steering wheel clockwise from the nine o’clock
position to the three o’clock position. If this clears the
message(s), the vehicle does not need servicing. If this
does not clear the message(s), then 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), the
vehicle should be taken in for service. For more
information on the DIC messages, seeDriver
Information Center (DIC) on page 3-51.
The StabiliTrak light will
ash on the instrument
panel cluster when the
system is both on and
activated.
The system may be heard or felt while it is 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 StabiliTrak button if
both systems (traction control and StabiliTrak) were
previously on. To disable both traction control and
StabiliTrak, press and hold the button for ve seconds.
Traction control and StabiliTrak can be turned on by
pressing and releasing the StabiliTrak button if not
automatically shut off for any other reason.
When the TCS or StabiliTrak system is turned off,
the StabiliTrak light and the appropriate TCS off or
StabiliTrak off message will be displayed on the DIC to
warn the driver. The 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,
system noises may still be heard as a result of the
brake-traction control coming on.
4-7