2004 GMC ENVOY maintenance

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-2
Rear Seats
............................................... 1-5
Safety Belts
.............................................. 1-8
Child Restraints
.......................................1-29
Air Bag Systems
......................................1-51
Restraint System Check
............................1-61
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
....................................... 2-8
Windows
.................................................2-15
Theft-Deterrent Systems
............................2-17
Starting and Operating Your Vehicle
...........2-19
Mirrors
....................................................2-36
OnStar
®System
......................................2-40
HomeLink®Transmitter
.............................2-41
Storage Areas
.........................................2-45
Sunroof
..................................................2-52
Vehicle Personalization
.............................2-52
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-20
Warning Lights, Gages and Indicators
.........3-32
Driver Information Center (DIC)
..................3-50
Audio System(s)
.......................................3-63Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-43
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-4
Checking Things Under the Hood
...............5-10
Rear Axle
...............................................5-49
Four-Wheel Drive
.....................................5-50
Front Axle
...............................................5-51
Bulb Replacement
....................................5-52
Windshield Wiper Blade Replacement
.........5-54
Tires
......................................................5-57
Appearance Care
.....................................5-91
Vehicle Identication
.................................5-99
Electrical System
....................................5-100
Capacities and Specications
...................5-115
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance and Information.............. 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-11
Index.................................................................1
2004 GMC Envoy/Envoy XL Owner ManualM

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag systems in several places
around your vehicle. Your dealer and the service
manual have information about servicing your vehicle
and the air bag systems. To purchase a service manual,
seeService Publications Ordering Information on
page 7-12.
{CAUTION:
For up to 10 minutes after the ignition key is
turned of and the battery is disconnected, an
air bag can still inate during improper
service. You can be injured if you are close to
an air bag when it inates. 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 qualied to do so.
The air bag systems do not need regular maintenance.
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.)
1-61

Notice:Modications 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.
Modications 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 Flashing— A misre condition has been
detected. A misre increases vehicle emissions
and may damage the emission control system on
your vehicle. Diagnosis and service may be
required.
Light On Steady— 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 “If
the Light Is On Steady” 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 “If
the Light Is On Steady” following. If the light is still
ashing, follow the previous steps, and see your dealer
for service as soon as possible.
3-41

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 SERVICE
ENGINE SOON or 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. 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.
3-43

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).
{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.
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 other problems causing
low oil pressure. United States
Canada
3-44

Off-Road Driving with Your
Four-Wheel Drive Vehicle
This off-road guide is for vehicles that have four-wheel
drive. Also, seeBraking on page 4-6. If your vehicle
does not have four-wheel drive, you should not
drive off-road unless you are on a level, solid surface.
Off-road driving can be great fun. But it does have some
denite hazards. The greatest of these is the terrain itself.
“Off-roading” means you have left the great North
American road system behind. Traffic lanes are not
marked. Curves are not banked. There are no
road signs. Surfaces can be slippery, rough, uphill or
downhill. In short, you have gone right back to nature.
Off-road driving involves some new skills. And that
is why it is very important that you read this guide. You
will nd many driving tips and suggestions. These
will help make your off-road driving safer and more
enjoyable.
Before You Go Off-Roading
There are some things to do before you go out.
For example, be sure to have all necessary maintenance
and service work done. Check to make sure all
underbody shields (if so equipped) are properly
attached.
Be sure you read all the information about your
four-wheel-drive vehicle in this manual.
Is there enough fuel? Is the spare tire fully inated?
Are the uid levels up where they should be? What are
the local laws that apply to off-roading where you
will be driving? If you do not know, you should check
with law enforcement people in the area. Will you be on
someone’s private land? If so, be sure to get the
necessary permission.
4-15

After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust
system for damage. Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service due to
off-road use. Refer to the Maintenance Schedule
for additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired — by alcohol or drugs, with night vision
problems, or by fatigue.
Here are some tips on night driving.
Drive defensively.
Do not drink and drive.
4-28

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t overll),
engine oil, axle lubricant, belt(s), cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd them quickly. If you’re
trailering, it’s a good idea to review these sections before
you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-65