wheel size GMC ENVOY 2008 Owner's Manual

Any object, such as an aftermarket seat heater or a
comfort enhancing pad or device, installed under or
on top of the seat fabric, could also interfere with
the operation of the passenger sensing system.
This could either prevent proper deployment of the
passenger airbag(s) or prevent the passenger
sensing system from properly turning off the
passenger airbag(s). SeePassenger Sensing
System on page 1-61.
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.
SeeCustomer Satisfaction Procedure on page 7-2.
If your vehicle has rollover roof-rail airbags, see
Different Size Tires and Wheels on page 5-76
for additional important information.Q:Because I have a disability, I have to get my
vehicle modied. How can I nd out whether
this will affect my airbag system?
A: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.
In addition, your dealer/retailer and the service manual
have information about the location of the airbag sensors,
sensing and diagnostic module and airbag wiring.
1-67

High-Speed Operation...................................5-66
Tire Pressure Monitor System.........................5-67
Tire Pressure Monitor Operation.....................5-69
Tire Inspection and Rotation...........................5-72
When It Is Time for New Tires.......................5-73
Buying New Tires.........................................5-74
Different Size Tires and Wheels......................5-76
Uniform Tire Quality Grading..........................5-77
Wheel Alignment and Tire Balance..................5-78
Wheel Replacement......................................5-78
Tire Chains..................................................5-80
Accessory Inator.........................................5-80
If a Tire Goes Flat........................................5-81
Changing a Flat Tire.....................................5-82
Removing the Spare Tire and Tools................5-84
Removing the Flat Tire and Installing the
Spare Tire................................................5-87
Secondary Latch System...............................5-92
Storing a Flat or Spare Tire and Tools............5-96
Spare Tire...................................................5-99
Appearance Care..........................................5-100
Interior Cleaning.........................................5-100
Fabric/Carpet..............................................5-101
Leather......................................................5-102
Instrument Panel, Vinyl, and Other
Plastic Surfaces.......................................5-102Care of Safety Belts....................................5-103
Weatherstrips.............................................5-103
Washing Your Vehicle..................................5-103
Cleaning Exterior Lamps/Lenses....................5-104
Finish Care................................................5-104
Windshield, Backglass, and Wiper Blades.......5-105
Aluminum Wheels.......................................5-105
Tires.........................................................5-106
Sheet Metal Damage...................................5-106
Finish Damage...........................................5-106
Underbody Maintenance...............................5-106
Chemical Paint Spotting...............................5-106
Vehicle Care/Appearance Materials................5-107
Vehicle Identication.....................................5-108
Vehicle Identication Number (VIN)................5-108
Service Parts Identication Label...................5-108
Electrical System..........................................5-109
Add-On Electrical Equipment.........................5-109
Headlamps.................................................5-109
Windshield Wiper Fuses...............................5-109
Power Windows and Other Power Options......5-109
Fuses and Circuit Breakers..........................5-110
Engine Compartment Fuse Block...................5-110
Rear Underseat Fuse Block..........................5-116
Capacities and Specications........................5-120
Section 5 Service and Appearance Care
5-2

Low-Prole Performance Tire
If your vehicle has P255/50R20 size tires, they are
classied as low-prole performance tires. These
tires are designed for very responsive driving on
wet or dry pavement. You may also notice more
road noise with low-prole performance tires and
that they tend to wear faster.
Notice:If your vehicle has low-prole tires,
they are more susceptible to damage from road
hazards or curb impact than standard prole
tires. Tire and/or wheel assembly damage can
occur when coming into contact with road
hazards like, potholes, or sharp edged objects,
or when sliding into a curb. Your vehicle
warranty does not cover this type of damage.
Keep tires set to the correct ination pressure
and, when possible avoid contact with curbs,
potholes, and other road hazards.
Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustration is an example
of a typical P-Metric tire sidewall.
(A) Tire Size
:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type,
and service description. See the “Tire Size”
illustration later in this section for more detail.
Passenger (P-Metric) Tire
5-58

Tire Size
The following examples show the different parts of
a tire size.
(A) Passenger (P-Metric) Tire
:The United States
version of a metric tire sizing system. The letter P
as the rst character in the tire size means a
passenger vehicle tire engineered to standards
set by the U.S. Tire and Rim Association.
(B) Tire Width
:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.(C) Aspect Ratio
:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the passenger (P-Metric) tire
illustration, it would mean that the tire’s sidewall is
75 percent as high as it is wide.
(D) Construction Code
:A letter code is used to
indicate the type of ply construction in the tire.
The letter R means radial ply construction;
the letter D means diagonal or bias ply
construction; and the letter B means belted-bias
ply construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Service Description
:The service description
indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
Speed ratings range from A to Z.
Passenger (P-Metric) Tire
5-60

Tire Pressure Monitor Operation
The Tire Pressure Monitor System (TPMS) is designed
to warn the driver when a low tire pressure condition
exists. TPMS sensors are mounted onto each tire
and wheel assembly, excluding the spare tire and wheel
assembly. The TPMS sensors monitor the air pressure
in the vehicle’s tires and transmit the tire pressure
readings to a receiver located in the vehicle.
The TPMS is designed to alert the driver if a low tire
pressure condition exists. If your vehicle has the Driver
Information Center (DIC) steering wheel control
buttons, tire pressure levels may also be checked
through the DIC. See “Tire Pressures” underDIC
Operation and Displays on page 3-50.
When a low tire pressure
condition is detected, the
TPMS illuminates the
low tire pressure warning
light located on the
instrument panel cluster.At the same time a message to check the pressure in a
specic tire appears on the Driver Information Center
(DIC) display. The low tire pressure warning light
and the DIC warning message come on at each ignition
cycle until the tires are inated to the correct ination
pressure. Using the DIC, tire pressure levels can be
viewed by the driver. For additional information and
details about the DIC operation and displays seeDIC
Operation and Displays on page 3-50andDIC Warnings
and Messages on page 3-53.
The low tire pressure warning light may come on in cool
weather when the vehicle is rst started, and then
turn off as you start to drive. This could be an early
indicator that the air pressure in the tire(s) is low
and needs to be inated to the proper pressure.
A Tire and Loading Information label, attached to your
vehicle, shows the size of your vehicle’s original
equipment tires and the correct ination pressure for
your vehicle’s tires when they are cold. SeeLoading
Your Vehicle on page 4-34, for an example of the Tire
and Loading Information label and its location on
your vehicle. Also seeInflation - Tire Pressure on
page 5-64.
5-69

GM recommends replacing tires in sets of four.
This is because uniform tread depth on all tires will
help keep your vehicle performing most like it did
when the tires were new. Replacing less than a full
set of tires can affect the braking and handling
performance of your vehicle. SeeTire Inspection
and Rotation on page 5-72for information on
proper tire rotation.
{CAUTION:
Mixing tires could cause you to lose
control while driving. If you mix tires of
different sizes, brands, or types (radial
and bias-belted tires) the vehicle may not
handle properly, and you could have a
crash. Using tires of different sizes,
brands, or types may also cause damage to
your vehicle. Be sure to use the correct
size, brand, and type of tires on your
vehicle’s wheels.
{CAUTION:
If you use bias-ply tires on your vehicle,
the wheel rim anges could develop
cracks after many miles of driving. A tire
and/or wheel could fail suddenly, causing a
crash. Use only radial-ply tires with the
wheels on your vehicle.
If you must replace your vehicle’s tires with those
that do not have a TPC Spec number, make sure
they are the same size, load range, speed rating,
and construction type (radial and bias-belted tires)
as your vehicle’s original tires.
5-75

Vehicles equipped with a tire pressure monitoring
system may give an inaccurate low-pressure
warning if non-TPC spec rated tires are installed
on your vehicle. Non-TPC Spec rated tires may
give a low-pressure warning that is higher or lower
than the proper warning level you would get with
TPC Spec rated tires. SeeTire Pressure Monitor
System on page 5-67.
Your vehicle’s original equipment tires are listed
on the Tire and Loading Information Label. See
Loading Your Vehicle on page 4-34, for more
information about the Tire and Loading Information
Label and its location on your vehicle.
Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could
affect the way your vehicle performs, including its
braking, ride and handling characteristics, stability, and
resistance to rollover. Additionally, if your vehicle has
electronic systems such as anti-lock brakes, rollover
airbags, traction control, and electronic stability control,
the performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your vehicle
may not provide an acceptable level of
performance and safety if tires not
recommended for those wheels are selected.
You may increase the chance that you will
crash and suffer serious injury. Only use GM
specic wheel and tire systems developed for
your vehicle, and have them properly installed
by a GM certied technician.
SeeBuying New Tires on page 5-74andAccessories
and Modifications on page 5-3for additional information.
5-76

Tire Chains
{CAUTION:
Do not use tire chains. There is not enough
clearance. Tire chains used on a vehicle
without the proper amount of clearance can
cause damage to the brakes, suspension, or
other vehicle parts. The area damaged by the
tire chains could cause you to lose control of
your vehicle and you or others may be injured in
a crash. Use another type of traction device only
if its manufacturer recommends it for use on
your vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, re-adjust or remove the
device if it is contacting your vehicle, and do
not spin your wheels. If you do nd traction
devices that will t, install them on the
rear tires.
Accessory Inator
Your vehicle may have an accessory inator system.
You can inate things like basketballs and bicycle tires.
You can also use it to bring your tire pressure up to
the proper pressure. It is not designed to inate large
objects which will require more than ve minutes to
inate, such as an air mattress.
The accessory inator is
located in the rear
compartment on the
driver’s side of the vehicle
behind an access cover,
near the liftgate opening.
To remove the cover, push in on the tab to access the
inator.
You may have an air inator kit that is located in the
glove compartment. It includes a 22 ft (6.7 m) hose with
three nozzle adapters.
5-80

1. Attach the handle (A), wheel wrench (B), and
extension (D) in the slots provided.
2. Roll up the instruction label (C) and return to the
slot in the tool kit.
3. Assemble the wheel blocks (F) to the jack.
4. Turn the knob (E) on the jack clockwise to raise the
jack head.
5. Return the rear seat to its proper position.
Spare Tire
Your vehicle, when new, had a fully-inated spare tire.
A spare tire may lose air over time, so check its
ination pressure regularly. SeeInflation - Tire Pressure
on page 5-64andLoading Your Vehicle on page 4-34
for information regarding proper tire ination and loading
your vehicle. For instruction on how to remove, install
or store a spare tire, seeRemoving the Flat Tire and
Installing the Spare Tire on page 5-87andStoring a Flat
or Spare Tire and Tools on page 5-96.After installing the spare tire on your vehicle, you should
stop as soon as possible and make sure the spare is
correctly inated. The spare tire is made to perform well
at speeds up to 70 mph (112 km/h) at the recommended
ination pressure, so you can nish your trip.
Have the damaged or at road tire repaired or replaced
as soon as you can and installed back onto your
vehicle. This way, a spare tire will be available in case
you need it again. Do not mix tires and wheels of different
sizes, because they will not t. Keep your spare tire and
its wheel together.
5-99

Tires.............................................................5-57
Aluminum Wheels, Cleaning........................5-105
Buying New Tires........................................5-74
Chains.......................................................5-80
Changing a Flat Tire....................................5-82
Cleaning...................................................5-106
Different Size..............................................5-76
High-Speed Operation..................................5-66
If a Tire Goes Flat.......................................5-81
Ination - Tire Pressure................................5-64
Inator,- Accessory.......................................5-80
Inspection and Rotation................................5-72
Installing the Spare Tire................................5-87
Pressure Monitor Operation...........................5-69
Pressure Monitor System..............................5-67
Removing the Flat Tire.................................5-87
Removing the Spare Tire and Tools...............5-84
Secondary Latch System..............................5-92
Spare Tire..................................................5-99
Storing a Flat or Spare Tire and Tools............5-96
Tire Sidewall Labeling..................................5-58
Tire Terminology and Denitions....................5-61
Uniform Tire Quality Grading.........................5-77
Wheel Alignment and Tire Balance.................5-78
Wheel Replacement.....................................5-78
When It Is Time for New Tires......................5-73Towing
Recreational Vehicle.....................................4-40
Towing a Trailer..........................................4-45
Your Vehicle...............................................4-40
Traction
StabiliTrak
®System....................................... 4-6
Transmission
Fluid, Automatic...........................................5-23
Transmission Operation, Automatic....................2-26
Trip Odometer................................................3-32
Turn and Lane-Change Signals.......................... 3-7
Turn Signal/Multifunction Lever........................... 3-7
U
Uniform Tire Quality Grading............................5-77
Universal Home Remote System.......................2-52
Operation...................................................2-52
Using this Manual............................................... iii
13