service CADILLAC XLR 2004 1.G Workshop Manual

Headlamp Aiming
Your vehicle has a visual optical headlamp aiming
system equipped with horizontal aim indicators. The aim
has been preset at the factory and should need no
further adjustment. This is true even though your
horizontal aim indicators may not fall exactly on
the ª0º (zero) marks on their scales.
If your vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment to the low beam
may be necessary if it is difficult to see lane markers (for
horizontal aim), or if oncoming drivers ¯ash their high
beams at you (for vertical aim). If you believe your
headlamps need to be re-aimed, we recommend that
you take your vehicle to your dealer for service.
However, it is possible for you to re-aim your headlamps
as described in the following procedure.
Notice:To make sure your headlamps are aimed
properly, read all the instructions before beginning.
Failure to follow these instructions could cause
damage to headlamp parts.
The vehicle should be properly prepared as follows:
·The vehicle should be placed so the headlamps are
25 ft. (7.6 m) from a light colored wall or other ¯at
surface.
·The vehicle must have all four tires on a perfectly
level surface which is level all the way to the wall
or other ¯at surface.
·The vehicle should be placed so it is perpendicular
to the wall or other ¯at surface.
·The vehicle should not have any snow, ice or mud
attached to it.
·The vehicle should be fully assembled and all other
work stopped while headlamp aiming is being done.
·The vehicle should be normally loaded with a
full tank of fuel and one person or 160 lbs (75 kg) on
the driver's seat.
·Tires should be properly in¯ated.
·Start the vehicle and rock it to level the suspension.
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Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service,
see your GM Warranty booklet for details. For additional
information refer to the tire manufacturer's booklet
included with your vehicle's Owner's Manual.
{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
·Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See ªLoading Your
Vehicleº in the Index.
·Underin¯ated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
CAUTION: (Continued)
CAUTION: (Continued)
·
Overin¯ated tires are more likely to be
cut, punctured or broken by a sudden
impact Ð such as when you hit a pothole.
Keep tires at the recommended pressure.
·Worn, old tires can cause accidents. If
your tread is badly worn, or if your tires
have been damaged, replace them.
Tire Sidewall Labeling
Useful information about a tire is molded into its
sidewall. The following illustration shows an example of
a passenger car tire sidewall.
5-50

A. Tire Size
B. Tire Performance Criteria Speci®cation (TPC Spec)
C. Department of Transportation (DOT)
D. Tire Identi®cation Number (TIN)
E. Tire Ply Material
F. Uniform Tire Quality Grading (UTQG)
G. Maximum Cold In¯ation Load Limit
(A) Tire Size:The tire size code is a combination of
letters and numbers used to de®ne a particular
tire's width, height, aspect ratio, construction type and
service description. See the ªTire Size º illustration later
in this section for more detail.
(B) Tire Performance Criteria Speci®cation (TPC
Spec):Original equipment tires designed to GM's
speci®c tire performance criteria have a TPC
speci®cation code molded onto the sidewall. GM's TPC
speci®cations meet or exceed all federal safety
guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
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(D) Tire Identi®cation Number (TIN):The letters and
numbers following DOT code are the Tire Identi®cation
Number (TIN). The TIN shows the manufacturer
and plant code, tire size, and date the tire was
manufactured. The TIN is molded onto both sides of the
tire, although only one side may have the date of
manufacture.
(E) Tire Ply Material:The type of cord and number of
plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):Tire
manufacturers are required to grade tires based on three
performance factors: treadwear, traction and
temperature resistance. For more information see
Uniform Tire Quality Grading on page 5-64.
(G) Maximum Cold In¯ation Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For more information on
recommended tire pressure see
In¯ation - Tire Pressure
on page 5-57andLoading Your Vehicle on page 4-32.
Tire Size Codes
The following illustration shows an example of a typical
passenger car tire size.
A. P-Metric Tire
B. Tire Width
C. Aspect RatioD. Construction Code
E. Rim Diameter
F. Service Description
5-52

(A) P-Metric Tire:The United States version of a
metric tire sizing system. The letter ªPº 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 ª70,º as shown in item ªCº of
the illustration, it would mean that the tire's sidewall is
70% 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
ªRº means radial ply construction; the letter ªDº means
diagonal or bias ply construction; and the letter ªBº
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:These characters represent
the load range and the speed rating of a tire. The
load range represents the load carrying 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 ªAº to ªZº.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)
before a tire has built up heat from driving. See
In¯ation - Tire Pressure on page 5-57.
5-53

Run-Flat Tires
Your vehicle, when new, had run-¯at tires. There's no
spare tire, no tire changing equipment and no place
to store a tire in the vehicle. Run-¯at tires perform so
well without any air that a Tire Pressure Monitor
(TPM) is used to alert you if a tire has lost pressure.
If a tire goes ¯at, you won't need to stop on the side of
the road to change the tire. You can just keep on
driving. The shorter the distance you drive and the
slower the speed, the greater the chance that the tire will
not have to be replaced. If you drive on a de¯ated
run- ¯at tire for 50 miles (80 km) or less and at speeds
of 55 mph (90 km/h) or less, there is a good chance
that the tire can be repaired. The tire can operate
effectively with no air pressure for up to 200 miles
(320 km) at speeds up to 55 mph (90 km/h), but the tire
would then have to be replaced. When a tire is ®lled
with air, it provides a cushion between the road and the
wheel. Because you won't have this cushion when
driving on a de¯ated tire, try to avoid potholes that could
damage your wheel and require replacement of it.Some road hazards can damage a tire beyond repair.
This damage could occur even before you've driven
on the tire in a de¯ated condition. When a tire has been
damaged, or if you've driven any distance on a
run-¯at tire, check with an authorized run-¯at tire service
center to determine whether the tire can be repaired
or should be replaced. To maintain your vehicle's run-¯at
feature, all replacement tires must be self-supporting
tires. As soon as possible, contact the nearest
authorized GM or run-¯at servicing facility for inspection
and repair or replacement. To locate the nearest GM
or run-¯at servicing facility, call Roadside Assistance.
For phone numbers and Roadside Service details
see
Roadside Service on page 7-5.
{CAUTION:
Run-¯at tires are constructed differently than
other tires and could explode during improper
service. You or others could be injured or
killed if you attempt to repair, replace,
dismount, or mount a run-¯at tire. Let only an
authorized run-¯at service center repair,
replace, dismount and mount run-¯at tires.
5-56

A low tire warning light also appears on the instrument
panel cluster when a low tire condition exists. The
DIC message, CHECK TIRE PRESSURE and the low
tire pressure warning light will be shown each time
the engine is started and stay on until the low tire
condition is corrected.
When the tire pressure
monitoring system warning
light is lit, one or more
of your tires is signi®cantly
under-in¯ated.
You should stop and check your tires as soon as
possible, and in¯ate them to the proper pressure as
indicated on the vehicle's tire information placard.
Driving on a signi®cantly under-in¯ated tire causes the
tire to overheat and can lead to tire failure.
Under-in¯ation also reduces fuel efficiency and tire tread
life, and may affect the vehicle's handling and stopping
ability. Each tire, including the spare, should be
checked monthly when cold and set to the
recommended in¯ation pressure as speci®ed in the
vehicle placard and owner's manual.The Tire and Loading Information Label (tire information
placard) is either on the rear edge of the driver's door
or the driver's door jamb near the latch. This label shows
the size of your vehicle's original tires and the correct
in¯ation pressure for your vehicle's tires when they
are cold. See
In¯ation - Tire Pressure on page 5-57.
Your vehicle's TPM system can alert you about a low or
high tire pressure condition but it does not replace
normal tire maintenance. See
Tire Inspection and
Rotation on page 5-60
Each TPM sensor has a unique identi®cation code that
is matched to one of the four tire positions on your
vehicle. The tire and wheel assembly positions are, left
front (LF); right front (RF); right rear (RR) and left
rear (LR). Any time you rotate your vehicle's tires or
replace one or more TPM sensors, the identi®cation
codes will need to be matched to the new tire and wheel
position. The TPM matching process is performed in
a speci®c sequence and time limit. A special tool is also
required. See your dealer for service.
The SVC TIRE MONITOR message is displayed when
the TPM system is malfunctioning. For example,
one or more TPM sensors may be inoperable or
missing. See your dealer for service.
5-59

The TPM system operates on a radio frequency subject
to Federal Communications Commission (FCC) Rules
and with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules and
with RSS-210 of Industry and Science Canada.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received
including interference that may cause undesired
operation of the device.
Changes or modi®cations to this system by other than
an authorized service facility could void authorization to
use this equipment.Tire Inspection and Rotation
Your vehicle's tires should be inspected regularly for
wear. Any time you notice unusual wear, rotate
your tires as soon as possible and check wheel
alignment. Also check for damaged tires or wheels. See
When It Is Time for New Tires on page 5-62andWheel Replacement on page 5-66for additional
information.
When rotating your vehicle's tires, always use the
correct rotation pattern shown here.
5-60

After the tires have been rotated, adjust the front and
rear in¯ation pressures as shown on the tire and loading
information label, see
In¯ation - Tire Pressure on
page 5-57andLoading Your Vehicle on page 4-32.
Vehicles equipped with the Tire Pressure Monitor (TPM)
system will need to have the sensors reset after a tire
rotation is performed. A special tool is needed to
reset the sensor identi®cation codes. See your dealer
for service. Make certain that all wheel nuts are properly
tightened. See
Wheel Replacement on page 5-66and
ªWheel Nut Torqueº underCapacities and Speci®cations
on page 5-91.
{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.
5-61

Buying New Tires
To ®nd out what kind and size of tires you need, look at
the Tire and Loading Information label. For information
about this label and where to ®nd it, see
Loading
Your Vehicle on page 4-32.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Speci®cation (TPC Spec)
number on each tire's sidewall. When you get new tires,
GM recommends that you get tires with that same
TPC Spec number. That way your vehicle will continue
to have tires that are designed to give proper
endurance, handling, speed rating, load range, traction,
ride, tire pressure monitoring system performance
and other things during normal service on your vehicle.
If your tires have an all-season tread design, the
TPC number will be followed by an ªMSº (for mud
and snow).
Whenever you replace your tires with those not having
a TPC Spec number, make sure they are the same
size, load range, speed rating and construction
type (bias, bias-belted or radial) as your original tires.
If you replace your vehicle's tires with those not having a
TPC Spec number, the tire pressure monitoring
system may give an inaccurate low-pressure warning.
Non-TPC Spec tires may give a low-pressure warning
that is higher or lower than the proper warning level you
would get with TPC Spec numbered tires.
{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
or types (radial and bias-belted tires), the
vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes may also cause damage to your vehicle.
Be sure to use the same size and type tires on
all 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.
5-63