2004 GMC SIERRA DENALI maintenance

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-3
Rear Seats
............................................... 1-8
Safety Belts
.............................................. 1-8
Child Restraints
.......................................1-29
Air Bag Systems
......................................1-62
Restraint System Check
............................1-79
Features and Controls..................................... 2-1
Keys
........................................................ 2-2
Doors and Locks
....................................... 2-6
Windows
.................................................2-13
Theft-Deterrent Systems
............................2-15
Starting and Operating Your Vehicle
...........2-18
Mirrors
....................................................2-31
OnStar
žSystem
......................................2-36
HomeLinkžTransmitter
.............................2-38
Storage Areas
.........................................2-42
Vehicle Personalization
.............................2-45
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-2
Climate Controls
......................................3-19
Warning Lights, Gages and Indicators
.........3-27
Driver Information Center (DIC)
..................3-46
Audio System(s)
.......................................3-64Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-48
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
................. 5-8
All-Wheel Drive
........................................5-46
Rear Axle
...............................................5-47
Front Axle
...............................................5-48
Bulb Replacement
....................................5-49
Windshield Wiper Blade Replacement
.........5-58
Tires
......................................................5-59
Appearance Care
.....................................5-96
Vehicle Identi®cation
...............................5-104
Electrical System
....................................5-105
Capacities and Speci®cations
...................5-114
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance and Information.............. 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-10
Index................................................................ 1
2004 GMC Sierra Denali Owner ManualM

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag system in several places
around your vehicle. You don't want the system to
in¯ate while someone is working on your vehicle. Your
dealer and the service manual have information
about servicing your vehicle and the air bag system. To
purchase a service manual, see
Service Publications
Ordering Information on page 7-11.
{CAUTION:
For up to 10 seconds after the ignition key is
turned off and the battery is disconnected, an
air bag can still in¯ate during improper
service. You can be injured if you are close to
an air bag when it in¯ates. Avoid yellow
connectors. They are probably part of the air
bag system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is quali®ed to do so.
The air bag system does not need regular maintenance.
Adding Equipment to Your Air
Bag-Equipped Vehicle
Q:Is there anything I might add to the front or
sides of the vehicle that could keep the air
bags from working properly?
A:Yes. If you add things that change your vehicle's
frame, bumper system, front end or side sheet
metal or height, they may keep the air bag system
from working properly. Also, the air bag system
may not work properly if you relocate any of the air
bag sensors. If you have any questions about
this, you should contact Customer Assistance
before you modify your vehicle. The phone
numbers and addresses for Customer Assistance
are in Step Two of the Customer Satisfaction
Procedure in this manual. See
Customer
Satisfaction Procedure on page 7-2
.
1-78

Q:Because I have a disability, I have to get my
vehicle modi®ed. How can I ®nd out whether
this will affect my advanced air bag system?
A:Changing or moving any parts of the front seats,
safety belts, the air bag sensing and diagnostic
module (located under the driver's seat), or
the inside rearview mirror can affect the operation
of the advanced air bag system. If you have
questions, call Customer Assistance. The phone
numbers and addresses for Customer Assistance
are in Step Two of the Customer Satisfaction
Procedure in this manual. See
Customer
Satisfaction Procedure on page 7-2
.
Restraint System Check
Checking Your Restraint Systems
Now and then, make sure the safety belt reminder light
and all your belts, buckles, latch plates, retractors
and anchorages are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from doing
its job, have it repaired.
Torn or frayed safety belts may not protect you in a
crash. They can rip apart under impact forces. If a belt
is torn or frayed, get a new one right away.
Also look for any opened or broken air bag covers, and
have them repaired or replaced. (The air bag system
does not need regular maintenance.)
1-79

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.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The Check Engine light comes on to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
3-40

Notice:If you keep driving your vehicle with this
light on, after a while, your emission controls
may not work as well, your fuel economy may not
be as good and your engine may not run as
smoothly. This could lead to costly repairs that may
not be covered by your warranty.
Notice:Modi®cations made to the engine,
transmission, exhaust, intake or fuel system of your
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle's emission
controls and may cause this light to come on.
Modi®cations to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to pass a required Emission
Inspection/Maintenance test.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is
not running. If the light does not come on, have it
repaired. This light will also come on during a
malfunction in one of two ways:
·Light FlashingÐ A mis®re condition has been
detected. A mis®re increases vehicle emissions
and may damage the emission control system on
your vehicle. Diagnosis and service may be
required.
·Light On SteadyÐ An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service may be required.
If the Light is Flashing
The following may prevent more serious damage to
your vehicle:
·Reducing vehicle speed.
·Avoiding hard accelerations.
·Avoiding steep uphill grades.
·If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops ¯ashing and remains on steady, see ªIf
the Light Is On Steadyº following.
If the light continues to ¯ash, when it is safe to do so,
stop the vehicle.Find a safe place to park your vehicle.
Turn the key off, wait at least 10 seconds and restart
the engine. If the light remains on steady, see ªIf
the Light Is On Steadyº following. If the light is still
¯ashing, follow the previous steps, and see your dealer
for service as soon as possible.
3-41

If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. See
Filling Your Tank on page 5-6. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. A loose or missing
fuel cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-4. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, mis®ring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
your dealer can check the vehicle. Your dealer has
the proper test equipment and diagnostic tools to ®x any
mechanical or electrical problems that may have
developed.
Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.
Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection if the Check
Engine light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection.
3-42

This can happen if you have recently replaced your
battery or if your battery has run down. The diagnostic
system is designed to evaluate critical emission
control systems during normal driving. This may take
several days of routine driving. If you have done this and
your vehicle still does not pass the inspection for lack
of OBD system readiness, your GM dealer can prepare
the vehicle for inspection.
Oil Pressure Gage
The oil pressure gage shows the engine oil pressure in
psi (pounds per square inch) when the engine is
running. Canadian vehicles indicate pressure in kPa
(kilopascals).Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
A reading in the low pressure zone may be caused
by a dangerously low oil level or some other problem
causing low oil pressure. Check your oil as soon
as possible. See
DIC Warnings and Messages on
page 3-57andEngine Oil on page 5-11.
{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches ®re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil. United States
Canada
3-43

Instant Fuel Economy
Press the fuel information button until INST ECON
appears in the display. Instant fuel economy is how
many miles per gallon your vehicle is getting at
the particular moment in time. The instant fuel economy
cannot be reset.
GM Oil Life System
Press the fuel information button until ENGINE OIL LIFE
appears in the display. The GM Oil Life System shows
an estimate of the oil's remaining useful life. It will show
100% when the system is reset after an oil change. It
will alert you to change your oil on a schedule consistent
with your driving conditions.
Always reset the engine oil life after an oil change. To
reset the Oil Life System use the fuel button to reach the
ENGINE OIL LIFE screen and then press and hold
the select button for ®ve seconds while ENGINE OIL
LIFE is displayed. OIL LIFE RESET will appear on
the display for 10 seconds to let you know the system is
reset.
The DIC does not replace the need to maintain your
vehicle as recommended in the Maintenance Schedule
in this manual. Also, the oil change reminder will not
detect dusty conditions or engine malfunctions that may
affect the oil. Also, the oil change reminder does notmeasure how much oil you have in your engine. So, be
sure to check your oil level often. See
Engine Oil on
page 5-11.
Personalization Button
You can program certain features to a preferred setting
for up to two people. Press the personalization button
to scroll through the following personalization features.
All of the personalization options may not be available
on your vehicle. Only the options available will be
displayed on your DIC.
If your vehicle is not equipped with the DIC steering
wheel buttons you will not have any of the following
personalization options except for DISPLAY
LANGUAGE. See DISPLAY LANGUAGE later in this
section for more information.
·AUTOMATIC LOCKING
·AUTOMATIC UNLOCKING
·DELAYED LOCKING
·REMOTE LOCK FEEDBACK
·ALARM WARNING TYPE
·REMOTE UNLOCK FEEDBACK
·HEADLAMPS ON AT EXIT
3-50