
(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:These characters represent
the load range and speed rating of the tire. The load
index represents the load carry capacity a tire is certi ed
to carry. The load index can range from 1 to 279. The
speed rating is the maximum speed a tire is certi ed
to carry a load. Speed ratings range from A to Z.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to
its width.Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrapped by
steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold In ation Pressure:The amount of air pressure in
a tire, measured in pounds per square inch (psi) or
kilopascals (kPa) before a tire has built up heat
from driving. SeeIn ation - Tire Pressure on page 5-58.
Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment including
the maximum capacity of fuel, oil and coolant, but
without passengers and cargo.
DOT Markings:A code molded into the sidewall of a
tire signifying that the tire is in compliance with the U.S.
Department of Transportation (DOT) motor vehicle
safety standards. The DOT code includes the Tire
Identi cation Number (TIN), an alphanumeric designator
which can also identify the tire manufacturer, production
plant, brand and date of production.
GVWR:Gross Vehicle Weight Rating, seeLoading
Your Vehicle on page 4-31.
5-54

Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the
wheel, wheel bolts and wheel nuts should be replaced.
If the wheel leaks air, replace it (except some
aluminum wheels, which can sometimes be repaired).
See your dealer if any of these conditions exist.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM
original equipment parts. This way, you will be sure to
have the right wheel, wheel bolts and wheel nuts
for your vehicle.{CAUTION:
Using the wrong replacement wheels, wheel
bolts or wheel nuts on your vehicle can be
dangerous. It could affect the braking and
handling of your vehicle, make your tires lose
air and make you lose control. You could have
a collision in which you or others could be
injured. Always use the correct wheel, wheel
bolts and wheel nuts for replacement.
Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance and tire clearance to the
body and chassis.
5-66

{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after a time. The wheel could
come off and cause a crash. When you change
a wheel, remove any rust or dirt from places
where the wheel attaches to the vehicle. In an
emergency, you can use a cloth or a paper
towel to do this; but be sure to use a scraper
or wire brush later, if you need to, to get all the
rust or dirt off.
{CAUTION:
Never use oil or grease on studs or the
threads of the wheel nuts. If you do, the wheel
nuts might come loose and the wheel could
fall off, causing a crash.
{CAUTION:
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to become
loose and even come off. This could lead to a
crash. Be sure to use the correct wheel nuts. If
you have to replace them, be sure to get new
GM original equipment wheel nuts.
Notice:Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque speci cation.
5-67

Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has been
used or how far it has been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
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.
5-68

Lifting Your Vehicle
{CAUTION:
Lifting a vehicle can cause an injury. The
vehicle can slip off the jack and roll over you
or other people. You and they could be badly
injured. Find a level place to lift your vehicle.
To help prevent the vehicle from moving:
1. Set the parking brake rmly.
2. Put an automatic transmission shift lever
in PARK (P), or shift a manual
transmission to FIRST (1) or
REVERSE (R).
3. Turn off the engine.
To be even more certain the vehicle won’t
move, you can put blocks in front of and
behind the wheels.
{CAUTION:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack, you
could be badly injured or killed. Never get
under a vehicle when it is supported only by
a jack.
{CAUTION:
Raising your vehicle with the jack improperly
positioned can damage the vehicle and even
make the vehicle fall. To help avoid personal
injury and vehicle damage, be sure to place
the jack in the proper location before raising
the vehicle.
If you ever use a jack to lift your vehicle, follow the
instructions that came with the jack, and be sure to use
the correct lifting points to avoid damaging your
vehicle.
5-69

Fuses Usage
SPARE FUSE
HOLDERSpare Fuse Holder
SPARE FUSE
HOLDERSpare Fuse Holder
SPARE FUSE
HOLDERSpare Fuse Holder
SPARE FUSE
HOLDERSpare Fuse Holder
TPA Tonneau Pulldown Actuator
ONSTAR OnStar
®
DRIV DR SW Driver Door Switch
TELE SW/MEM
SEAT MODTelescope Switch, Memory Seat
Module
IGN SW/
INTR SENSIgnition Switch, Intrusion Sensor
REVERSE
LAMPReverse Lamp
REVERSE
LAMPSReverse Lamps
Blank Not Used
STOP LAMP Stop Lamp
BTSI SOL/
COL LOCKBrake Transmission Shift Interlock,
Column Lock
BLANK Not Used
Fuses Usage
RADIO/
S-BAND/VICSRadio, S-Band, VICS
REAR
FOG/ALDL/
TOP SWRear Fog Lamp, Assembly Line
Diagnostic Link Connector,
Convertible Top Switch
GMLAN
DEVICESGMLAN Devices
ISRVM/ HVACElectric Inside Rearview Mirror,
Heating Ventilation, Air Conditioning
CRUISE SW Cruise Control Switch
TONNEAU
RELSETonneau Release
RUN/CRANK Run/Crank Relay
HTD SEAT/
WPR RELAYSHeated Seat, Wiper Relays
ECM Engine Control Module
SDM PSIR SW
AIRBAGSDM/PSIR Switch (Airbag)
CLSTR/HUD Cluster, Heads-Up Display
HVAC/
PWR SNDHeating, Ventilation/Air Conditioning,
Power Sounder
SPARE Spare
DR LCK Door Locks
CTSY/LAMP Courtesy Lamp
BLANK Not Used
5-87

Fuse Usage
1Transmission Control
Module/Transmission
2 Horn, Alternator Sense
3 Anti-lock Brakes/Real Time Damping
4 Wiper
5 Stoplamps/Back-Up Lamps
6 02 Sensor
7 Battery Main 5
8 Park Lamps
9Powertrain Relay Input/Electronic
Throttle Control
10 Manual Transmission Solenoids
11Engine Control Module/Transmission
Control Module/Easy Key Module
12 Odd Numbered Fuel Injectors
13 Real Time Damping
14Canister Purge Solenoid, Mass Air
Flow Sensor
15 Air Conditioner Compressor
16 Even Numbered Fuel Injectors
17 Windshield WasherFuse Usage
18 Headlamp Washer
19 Right Low-Beam
20 Fuel Pump
21 Left Low-Beam
22 Front Fog Lamp
23 Right High-Beam
24 Left High-Beam
J-Style Fuses Usage
25 Cooling Fan
26 Battery Main 3
27 Anti-Lock Brake System
28Heating/Ventilation/Air Conditioning
Blower
29 Battery Main 2
30 Starter
31 Audio Ampli er
32 Blank
33 Battery Main 1
5-90