2004 GMC SIERRA brake

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 4-53.
{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. United States
Canada
3-44

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. If the light doesn't come on then, have it
®xed so it will be ready to warn you if there is a
problem.
If the light stays on, or comes on when you're driving,
your vehicle needs service. You will also hear a
chime sound when the light is on steady. 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. In addition to both lights, you will
also hear a chime sound on the ®rst occurrence of
a problem and each time the vehicle is shut off and then
restarted. See
Brake System Warning Light on
page 3-43.
Traction Off Light
If you have the Traction
Assist System, this light
should come on brie¯y
when you turn the ignition
to RUN.
If the light doesn't come on then, the system may
require service; have it ®xed so it will be there to warn
you if the system is turned off.
If the light stays on, or comes on when you're driving,
there may be a problem with your Traction Assist
System and your vehicle may need service. When this
light is on, the system will not limit wheel spin. Adjust
your driving accordingly.
3-45

The traction off light may come on for the following
reasons:
·If you turn the system off by pressing the TAS
on/off button located to the left of the steering wheel,
the light will come on and stay on. To turn the
system back on, press the button again; the light
should go off.
·If you move the shift lever to FIRST (1), the light
will come on and stay on to indicate that the
traction system is off. This is normal operation. To
turn the system back on, move the shift lever
back to a position other than FIRST (1); the light
should go off. See
Traction Assist System (TAS) on
page 4-9.
·The light will come on and stay on if the TAS
automatic engagement feature has been turned off.
To turn the system on, press the TAS off/on
button; the light should go off. To turn the automatic
engagement feature back on, see
Traction Assist
System (TAS) on page 4-9.
·If the Traction Assist System is affected by an
anti-lock brake system, TAS or engine-related
problem, the system will turn off and the light will
come on. Have your vehicle serviced.
·If the vehicle is driven over an extremely rough road,
the system will turn off and the light will come on. The
light will go off a few seconds after the rough road
conditions go away or when the vehicle comes to a
complete stop. This is normal operation.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.United States
Canada
3-46

If your vehicle has an Allison transmission, and the ¯uid
reaches temperatures of approximately 275ÉF (135ÉC)
or greater, the driver information center will display
a TRANS HOT IDLE ENGINE warning message and a
chime will sound until the temperature falls below
265ÉF (129ÉC). Pull the vehicle off the roadway when it
is safe to do so. Set the parking brake, place the
transmission in PARK (P) and allow the engine to idle
until the transmission temperature falls below 265ÉF
(129ÉC). If the transmission continues to operate above
265ÉF (130ÉC), contact your nearest dealer or the
GM Roadside Assistance Center. See
Roadside
Assistance Program on page 7-6.
Notice:If you drive your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.The following situations can cause the transmission to
operate at higher temperatures:
·Towing a trailer
·Hot outside air temperatures
·Hauling a large or heavy load
·Low transmission ¯uid level
·High transmission ¯uid level
·Restricted air ¯ow to the radiator and the auxiliary
transmission oil cooler (if equipped).
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, see
Scheduled Maintenance
on page 6-4for the proper transmission maintenance
intervals.
3-48

REDUCED ENGINE POWER
This message is displayed when the cooling system
temperature gets too hot and the engine further enters
the engine coolant protection mode.
See
Engine Overheating on page 5-36for further
information.
RIGHT REAR DOOR AJAR (Crew Cab)
If the passenger's side rear door is not fully closed,
this message will appear on the display and you
will hear a chime. Stop and turn off the vehicle, check
the door for obstacles, and close the door again. Check
to see if the message still appears on the DIC. Press
the select button to acknowledge the message and clear
it from the DIC display.
SERVICE AIRBAG
If there is a problem with the air bag system, this
message will be displayed on the DIC. Have a quali®ed
technician inspect the system for problems. Press
the select button to acknowledge the message and clear
it from the DIC display.
SERVICE BRAKE SYSTEM
If there is a problem with the brake system, this
message will be displayed 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.
SERVICE BRAKE BOOSTER
If your vehicle has vaccum assist power brakes, this
message will be displayed on the DIC when there is a
problem with the Supplemental Brake Assist system.
If the message is displayed immediately after starting
the vehicle or the message appears while driving,
your Supplemental Brake Assist system needs service.
See
Brake System Warning Light on page 3-43.
3-70

{CAUTION:
Your brake system may not be working
properly if the SERVICE BRAKE BOOSTER
message is displayed.
If the brake system warning light is also on, you
should have the vehicle towed for service. See
ªBrake System Warning Lightº in the Index.
If the brake system warning light isn't on, you
still have brakes, but the supplemental brake
assist system may not operate properly. In the
event of a vacuum loss, you may not have
vacuum power assist for braking. The brake
pedal will be harder to push and it will take
longer to stop. If you continue to drive with this
message displayed it can lead to a crash. Have
the brake system serviced as soon as possible.
SERVICE 4 WHEEL STEER
If a problem occurs with the 4 wheel steer 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 being driving, the four wheel
steer system needs service.
SERVICE 4WD
If a problem occurs with the four wheel drive 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 four wheel
drive system needs service.
SERVICE RIDE CONTROL
If a problem occurs with the suspension system, this
message will appear on the DIC. If this message
appears, stop 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 air suspension system
needs service.
3-71

Your Driving, the Road, and
Your Vehicle
Defensive Driving
The best advice anyone can give about driving is: Drive
defensively.
Please start with a very important safety device in your
vehicle: Buckle up. See
Safety Belts: They Are for
Everyone on page 1-11.
Defensive driving really means ªbe ready for anything.º
On city streets, rural roads or freeways, it means
ªalways expect the unexpected.º
Assume that pedestrians or other drivers are going to
be careless and make mistakes. Anticipate what
they might do. Be ready for their mistakes.
Rear-end collisions are about the most preventable of
accidents. Yet they are common. Allow enough following
distance. It is the best defensive driving maneuver, in
both city and rural driving. You never know when
the vehicle in front of you is going to brake or turn
suddenly.
Defensive driving requires that a driver concentrate on
the driving task. Anything that distracts from the driving
task Ð such as concentrating on a cellular telephone call,
reading, or reaching for something on the ¯oor Ð makesproper defensive driving more difficult and can even
cause a collision, with resulting injury. Ask a passenger to
help do things like this, or pull off the road in a safe place
to do them yourself. These simple defensive driving
techniques could save your life.
Drunken Driving
Death and injury associated with drinking and driving is
a national tragedy. It is the number one contributor
to the highway death toll, claiming thousands of victims
every year.
Alcohol affects four things that anyone needs to drive a
vehicle:
·Judgment
·Muscular Coordination
·Vision
·Attentiveness.
Police records show that almost half of all motor
vehicle-related deaths involve alcohol. In most cases,
these deaths are the result of someone who was
drinking and driving. In recent years, more than
16,000 annual motor vehicle-related deaths have been
associated with the use of alcohol, with more than
300,000 people injured.
4-2

{CAUTION:
Drinking and then driving is very dangerous.
Your re¯exes, perceptions, attentiveness and
judgment can be affected by even a small
amount of alcohol. You can have a serious Ð
or even fatal Ð collision if you drive after
drinking. Please do not drink and drive or ride
with a driver who has been drinking. Ride
home in a cab; or if you are with a group,
designate a driver who will not drink.
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.
4-5