
Black plate (1,1)Cadillac STS Owner Manual - 2011
Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-4
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-5
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-5
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . . 6-8
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-11
Checking Things Under the Hood . . . . . . . . . . . . . . .6-12
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-13
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-21
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . 6-23
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24
Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30 Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-33
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-34
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-43
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-45
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-46
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47
High Intensity Discharge (HID) Lighting . . . . . . . . 6-47
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47
Back-Up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48
Windshield Replacement . . . . . . . . . . . . . . . . . . . . . . . . .6-48
Windshield Wiper Blade Replacement . . . . . . . . . . .6-49
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Tire Terminology and Definitions . . . . . . . . . . . . . . . 6-55
Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . 6-58
High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
6-1

Black plate (15,1)Cadillac STS Owner Manual - 2011
After you have removed the sight shields (if equipped):A. Underhood Fuse Block. See Underhood Fuse
Block on page 6‑116.
B. Remote Negative (-) Terminal. See Jump Starting
on page 6‑38.
C. Remote Positive (+) Terminal. See Jump Starting
on page 6‑38.
D. Battery. See Battery on page 6‑38.
E. Passenger Compartment Air Filter. See Passenger
Compartment Air Filter on page 4‑50.
F. Power Steering Fluid Reservoir. See Power
Steering Fluid on page 6‑33.
G. Engine Oil Fill Cap. See “When to Add Engine Oil”
under Engine Oil on page 6‑16.
H. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 6‑16. I. Brake Master Cylinder Reservoir. See
“Brake
Fluid” under Brakes on page 6‑35.
J. Engine Coolant Surge Tank and Pressure Cap. See Cooling System on page 6‑24.
K. Engine Air Cleaner/Filter. See Engine Air Cleaner/
Filter on page 6‑21.
L. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on
page 6‑34.
If your vehicle is equipped with front compartment
underhood sight shields, before closing the hood be
sure to reinstall the sight shields. To reinstall the
shields, locate the tabs on the left and right sides and
insert them into the openings in the tower to tower
brace. Then insert the fasteners into the top of the
shield and push the fasteners back into place.
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Black plate (33,1)Cadillac STS Owner Manual - 2011
Power Steering Fluid
SeeEngine Compartment
Overviewon page 6‑13for reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering
fluid unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired.
How to Check Power Steering Fluid
To check the power steering fluid, do the following:
1. Turn the ignition off and let the engine compartment cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the dipstick.
The level should be within the HOT mark. If necessary,
add only enough fluid to bring the level within the mark.
What to Use
To determine what kind of fluid to use, see
Recommended Fluids and Lubricantson page 7‑9.
Always use the proper fluid.
Notice: Use of the incorrect fluid may damage the
vehicle and the damages may not be covered by the
vehicle's warranty. Always use the correct fluid
listed in Recommended Fluids and Lubricants
on
page 7‑9.
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Black plate (55,1)Cadillac STS Owner Manual - 2011
(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 60, as
shown in item C of the illustration, it would mean
that the tire's sidewall is 60 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
:These characters
represent the load index and speed rating of the
tire. The load index represents the load carrying
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load.
Tire Terminology and Definitions
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.
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Black plate (117,1)Cadillac STS Owner Manual - 2011
The underhood fuse block is located in the front of the
engine compartment on the passenger side of the
vehicle. SeeEngine Compartment Overview
on
page 6‑13for more information on location and
removal procedure for the front compartment underhood
sights shields.
To access the fuses, push in the tabs located on each
side of the fuse block cover, then lift the cover off.
Notice: Spilling liquid on any electrical component
on the vehicle may damage it. Always keep the
covers on any electrical component.
Fuses JCase Usage
ABS MTR ABS Module- ABS Module-Stabilitrak AFS Active Front Steering
BLWR Blower Motor
FAN 1 Cooling Fan-Low Speed
FAN 2 Cooling Fan-High Speed
LPDB 1 Driver Side Rear Fuse Block
LPDB 2 Driver Side Rear Fuse Block
RPDB 1 Passenger Side Rear Fuse Block
RPDB 2 Passenger Side Rear Fuse Block
Fuses JCase Usage
SPARE Spare
SPARE Spare
STRTR Starter
Fuses MiniUsage
A/C CLTCH Air Conditioning Compressor Clutch
ABS ABS Module-Stabilitrak
ABS IGN Antilock Brake Controller
AUX OUTLET Rear Accessory Power Outlet BRK
VAC PUMP Brake Vacuum Pump
CCP Climate Control Panel
CCP/RLY COILS Climate Control Panel, Headlamp
Level Control, Active Cruise Control,
Relay Coils, Starter, Front Blower
ECM 1 Engine Control Module (ECM)
ECM/TCM BATT ECM, Transmission Control
Module (TCM)
ECM/TCM IGN ECM, TCM, Instrument Panel Cluster
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Black plate (118,1)Cadillac STS Owner Manual - 2011
Fuses MiniUsage
EKM/I/P MDLEasy Key Module (EKM), Instrument
Panel Module (I/P MDL)
EVEN COILS Even Ignition Coils, Even Fuel
Injectors
FOG LAMP Front Fog Lamps
FRT PWR OUTLET Front Accessory Power Outlet
FUEL COOL Fuel Cooling HORN Horn
HTD
WASH/AQS Heated Headlamp Washer, Air Quality
Sensor
HUD Heads-Up Display, Steering Column
Switch
I/BEAM IntelliBeam Relay
I/P MDL/ALDL Instrument Panel Module, Assembly
Line Data Link Connector
LIC DIM License Plate, Instrument Panel
Dimming
LT HI BEAM Driver Side High Beam Headlamp
LT LO BEAM Driver Side Low Beam Headlamp
Fuses Mini Usage
LT PRKDriver Side Park Lamp/Driver Side
Taillamp
ODD COILS Odd Ignition Coils, Odd Fuel Injectors
POST O2 SNSR Post Oxygen Sensor PRE O2 SNSR Pre Oxygen Sensor, CAM Sensors
RAIN
SNSR/TPM Rain Sensor, Relay Coil:
Headlamp Wash
RT HI BEAM Passenger Side High Beam
Headlamp
RT LO BEAM Passenger Side Low Beam Headlamp
RT PRK Passenger Side Park Lamp,
Passenger Side Taillamp
SPARE Spare
SPARE Spare
SPARE Spare
SPARE Spare
SPARE Spare
SPARE Spare
SPARE Spare
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Black plate (126,1)Cadillac STS Owner Manual - 2011
FusesUsage
AIRBAG/IGNSensing and Diagnostic Monitor,
Automatic Occupant Sensor,
Passenger Supplemental Inflatable
Restraint
CNSTR/VENT Canister Vent Solenoid
SPARE Spare
FRT PDM Front Passenger Door Module, Right
Power Subwoofer
FUEL PUMP Fuel Pump
HTD STR Heated Steering WheelRF HTD/
SEAT/XM Front Passenger Heated Seat,
S-Band™
Antenna
RDO/ONSTAR Radio, OnStar
®
INT LAMP Interior Lamps
LT TRN/LDW Left Turn Signal, Lane Departure
Warning (Option)
Fuses
Usage
REAR DEFOG Rear Defogger
REAR/FOG Rear Fog Lamps (Option)
RIM Rear Integration Module
RIM /RPA
/ISRVM /CLM Rear Integration Module, Rear
Parking Aid, Inside Rearview Mirror,
Column Lock Module, Power
Sounder, Active Front Steering (AFS),
Supervisory Control Module
RUN/CRNK UHBEC Run, CRNK Relay Coil, Rear
Fog Lamp Relay Coil
S/ROOF Sun Roof Module (Option) SPARE Spare
STOP LAMPS Stop Lamps
RT TRN/SZBA Right Turn Signal, Side Blind Zone
Alert (Option)
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Black plate (9,1)Cadillac STS Owner Manual - 2011
Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number, or specification can be obtained from your
dealer.Usage Fluid/Lubricant
Engine Oil The engine requires engine oil
approved to the dexos™
specification.
Oils meeting this specification can
be identified with the dexos™
certification mark. Look for and use
only an engine oil that displays the
dexos™ certification mark of the
proper viscosity grade. See Engine
Oil on page 6‑16.
Engine Cooling System 50/50 mixture of clean, drinkable
water and use only DEX-COOL
Coolant. See
Engine Coolant
on
page 6‑25.
Usage Fluid/Lubricant
Hydraulic Brake
System DOT 3 Hydraulic Brake Fluid
(GM Part No. U.S. 12377967, in
Canada 89021320).
Windshield Washer Optikleen
®Washer Solvent.
Parking Brake Cable Guides Chassis Lubricant (GM Part No.
U.S. 12377985, in Canada 88901242)
or lubricant meeting requirements of
NLGI #2, Category LB or GC-LB.
Power Steering System GM Power Steering Fluid
(GM Part No. U.S. 89021184, in
Canada 89021186).
Automatic
Transmission DEXRON
®-VI Automatic Transmission
Fluid.
Key Lock
Cylinders Multi-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
7-9