2005 GMC ENVOY XL Owners Manual

Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear, under heavy
loads or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating on
page 5-26.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the
trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
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4. Reapply the regular brakes. Then apply your
parking brake, and then shift into PARK (P).
5. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not in
NEUTRAL.
SeeFour-Wheel Drive on page 2-27.
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.
4-64

Trailer Wiring Harness
Your vehicle may be equipped with the seven-wire
trailer towing harness. This harness has a seven-pin
universal heavy-duty trailer connector that is attached to
a bracket on the hitch platform. The seven-wire
harness contains the following trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Running Lamps
White: Ground
Light Green: Back-up Lamps
Dark Blue: Electric Brakes
Red: Battery Feed (The chassis wiring ring
terminal must be fastened to a stud on the
underhood electrical center before the trailer feed
will become active.)
If you need to tow a light-duty trailer with a standard
four-way round pin connector, an adapter connector is
available from your dealer.
Your vehicle may also be equipped with wiring for an
electric trailer brake controller. These wires are located
inside the vehicle on the driver’s side under the
instrument panel. These wires should be connected to
an electric trailer brake controller by your dealer or
a qualied service center.
4-65

✍NOTES
4-66

Service............................................................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of Your Vehicle...........................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-19
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-23
Radiator Pressure Cap..................................5-26
Engine Overheating.......................................5-26
Cooling System............................................5-28
Engine Fan Noise.........................................5-33
Power Steering Fluid.....................................5-34Windshield Washer Fluid................................5-34
Brakes........................................................5-35
Battery........................................................5-38
Jump Starting...............................................5-39
Rear Axle.......................................................5-43
Four-Wheel Drive............................................5-44
Front Axle......................................................5-44
Bulb Replacement..........................................5-45
Halogen Bulbs..............................................5-45
Headlamps, Front Turn Signal, Sidemarker,
and Parking Lamps....................................5-46
Taillamps, Turn Signal, and Stoplamps............5-46
Back-Up Lamps............................................5-47
Replacement Bulbs.......................................5-47
Windshield Wiper Blade Replacement..............5-48
Tires..............................................................5-50
Tire Sidewall Labelling...................................5-51
Tire Terminology and Denitions.....................5-54
Ination - Tire Pressure.................................5-56
Tire Inspection and Rotation...........................5-57
When It Is Time for New Tires.......................5-59
Buying New Tires.........................................5-59
Uniform Tire Quality Grading..........................5-60
Wheel Alignment and Tire Balance..................5-61
Section 5 Service and Appearance Care
5-1

Wheel Replacement......................................5-62
Tire Chains..................................................5-63
Accessory Inator.........................................5-64
If a Tire Goes Flat........................................5-65
Changing a Flat Tire.....................................5-66
Removing the Spare Tire and Tools................5-67
Removing the Flat Tire and Installing
the Spare Tire..........................................5-70
Secondary Latch System...............................5-75
Storing a Flat or Spare Tire and Tools............5-78
Spare Tire...................................................5-81
Appearance Care............................................5-81
Cleaning the Inside of Your Vehicle.................5-82
Fabric/Carpet...............................................5-83
Leather.......................................................5-84
Instrument Panel, Vinyl, and Other Plastic
Surfaces..................................................5-84
Care of Safety Belts......................................5-85
Weatherstrips...............................................5-85
Washing Your Vehicle...................................5-85
Cleaning Exterior Lamps/Lenses.....................5-85
Finish Care..................................................5-86Windshield, Backglass, and Wiper Blades.........5-86
Aluminum Wheels.........................................5-87
Tires...........................................................5-88
Sheet Metal Damage.....................................5-88
Finish Damage.............................................5-88
Underbody Maintenance................................5-88
Chemical Paint Spotting.................................5-88
Vehicle Care/Appearance Materials..................5-89
Vehicle Identication......................................5-90
Vehicle Identication Number (VIN).................5-90
Service Parts Identication Label.....................5-90
Electrical System............................................5-91
Add-On Electrical Equipment..........................5-91
Headlamps..................................................5-91
Windshield Wiper Fuses................................5-91
Power Windows and Other Power Options.......5-91
Fuses and Circuit Breakers............................5-91
Engine Compartment Fuse Block....................5-92
Rear Underseat Fuse Block...........................5-98
Capacities and Specications........................5-103
Section 5 Service and Appearance Care
5-2

Service
Your dealer knows your vehicle best and wants you to
be happy with it. We hope you will go to your dealer
for all your service needs. You will get genuine GM parts
and GM-trained and supported service people.
We hope you will want to keep your GM vehicle all GM.
Genuine GM parts have one of these marks:
California Proposition 65 Warning
Most motor vehicles, including this one, contain and/or
emit chemicals known to the State of California to
cause cancer and birth defects or other reproductive
harm. Engine exhaust, many parts and systems
(including some inside the vehicle), many uids, and
some component wear by-products contain and/or emit
these chemicals.
5-3

Doing Your Own Service Work
If you want to do some of your own service work, you
will want to use the proper service manual. It tells
you much more about how to service your vehicle than
this manual can. To order the proper service manual,
seeService Publications Ordering Information on
page 7-11.
Your vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-66.
You should keep a record with all parts receipts and
list the mileage and the date of any service work
you perform. SeeMaintenance Record on page 6-15.{CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts,
and tools before you attempt any vehicle
maintenance task.
Be sure to use the proper nuts, bolts,
and other fasteners. English and metric
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
5-4