2008 CADILLAC DTS octane

If the Light is Flashing
The following can prevent more serious damage to your
vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops ashing and remains on steady,
see “If the Light Is On Steady” following.
If the light continues to ash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the ignition off, wait at least 10 seconds, and restart
the engine. If the light remains on steady, see “If the
Light Is On Steady” following. If the light is still ashing,
follow the previous steps and see your dealer/retailer
for service as soon as possible.
If the Light Is On Steady
You might be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully
install the cap. SeeFilling the Tank on page 5-8.
The diagnostic system can determine if the fuel
cap has been left off or improperly installed.A loose or missing fuel cap allows fuel to evaporate
into the atmosphere. A few driving trips with the
cap properly installed should turn the light off.
Did you just drive through a deep puddle of water?
If so, your vehicle’s electrical system might be wet. The
condition is usually corrected when the electrical system
dries out. A few driving trips should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-5. Poor fuel quality causes
the engine not to run as efficiently as designed. You
might notice this as stalling after start-up, stalling when
you put the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration — these
conditions might go away once the engine is warmed up.
This will be detected by the system and cause the light to
turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
your dealer/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.
3-66

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials
Requirements.............................................5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of the 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.....................5-11
Checking Things Under the Hood....................5-12
Hood Release..............................................5-12
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-20
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-24
Coolant Surge Tank Pressure Cap..................5-27Engine Overheating.......................................5-27
Overheated Engine Protection
Operating Mode........................................5-29
Cooling System............................................5-30
Power Steering Fluid.....................................5-35
Windshield Washer Fluid................................5-36
Brakes........................................................5-37
Battery........................................................5-40
Jump Starting...............................................5-42
Headlamp Aiming...........................................5-47
Bulb Replacement..........................................5-50
High Intensity Discharge (HID) Lighting..............5-50
Windshield Wiper Blade Replacement..............5-50
Tires..............................................................5-52
Tire Sidewall Labeling...................................5-53
Tire Terminology and Denitions.....................5-57
Ination - Tire Pressure.................................5-60
High-Speed Operation...................................5-62
Tire Pressure Monitor System.........................5-63
Tire Pressure Monitor Operation.....................5-64
Tire Inspection and Rotation...........................5-68
When It Is Time for New Tires.......................5-70
Buying New Tires.........................................5-71
Different Size Tires and Wheels......................5-73
Section 5 Service and Appearance Care
5-1

Your vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-68.
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 6-16.
Adding Equipment to the Outside
of the Vehicle
Things you might add to the outside of your vehicle
can affect the airow around it. This can cause
wind noise and can affect fuel economy and windshield
washer performance. Check with your dealer/retailer
before adding equipment to the outside of your vehicle.
Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle. To help keep the
engine clean and maintain optimum vehicle performance,
we recommend the use of gasoline advertised as TOP
TIER Detergent Gasoline.
Gasoline Octane
Use premium unleaded gasoline with a posted octane
rating of 91 or higher. You can also use regular unleaded
gasoline rated at 87 octane or higher, but your vehicle’s
acceleration could be slightly reduced, and you might
notice a slight audible knocking noise, commonly referred
to as spark knock. If the octane is less than 87, you might
notice a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you could damage the
engine. If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine needs
service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 or 3.511 in Canada. Some gasolines
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT).
We recommend against the use of gasolines
containing MMT. SeeAdditives on page 5-6
for additional information.
5-5

Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under your
warranty.
Some gasolines that are not reformulated for
low emissions can contain an octane-enhancing
additive called methylcyclopentadienyl manganese
tricarbonyl (MMT); ask the attendant where you
buy gasoline whether the fuel contains MMT. We
recommend against the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs
and the performance of the emission control system
could be affected. The malfunction indicator lamp might
turn on. If this occurs, return to your dealer/retailer
for service.Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might be hard
to nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
be covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-7

Using the Maintenance Schedule
We want to help you keep your vehicle in good working
condition. But we do not know exactly how you will
drive it. You might drive very short distances only a few
times a week. Or you might drive long distances all
the time in very hot, dusty weather. You might use your
vehicle in making deliveries. Or you might drive it to
work, to do errands, or in many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You might need more
frequent checks and replacements. So please read
the following and note how you drive. If you have any
questions on how to keep your vehicle in good condition,
see your dealer/retailer.
This schedule is for vehicles that:
carry passengers and cargo within recommended
limits. You will nd these limits on the Tire and
Loading Information label. SeeLoading the Vehicle
on page 4-20.
are driven on reasonable road surfaces within legal
driving limits.
use the recommended fuel. SeeGasoline Octane
on page 5-5.The services inScheduled Maintenance on page 6-4
should be performed when indicated. SeeAdditional
Required Services on page 6-6andMaintenance
Footnotes on page 6-8for further information.
{CAUTION:
Performing maintenance work on a vehicle can
be dangerous. In trying to do some jobs, you
can be seriously injured. Do your own
maintenance work only if you have the
required know-how and the proper tools and
equipment for the job. If you have any doubt,
see your dealer/retailer to have a qualied
technician do the work. SeeDoing Your Own
Service Work on page 5-4.
Some maintenance services can be complex.
So, unless you are technically qualied and have
the necessary equipment, you should have your
dealer/retailer do these jobs.
6-3

Fuel............................................................... 5-5
Additives...................................................... 5-6
California Fuel.............................................. 5-6
Filling a Portable Fuel Container....................5-11
Filling the Tank............................................. 5-8
Fuels in Foreign Countries.............................. 5-7
Gage .........................................................3-69
Gasoline Octane........................................... 5-5
Gasoline Specications.................................. 5-5
Running Out of...........................................2-35
Fuses
Fuses and Circuit Breakers.........................5-101
Rear Underseat Fuse Block.........................5-104
Underhood Fuse Block...............................5-101
Windshield Wiper.......................................5-100
G
Gage
Engine Coolant Temperature.........................3-64
Fuel..........................................................3-69
Speedometer..............................................3-55
Tachometer.................................................3-55
Garage Door Opener.......................................2-52
Gasoline
Octane........................................................ 5-5
Specications............................................... 5-5
Glove Box.....................................................2-59
GM Mobility Reimbursement Program.................. 7-7
H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-7
Headlamp
Aiming .......................................................5-47
Headlamp Wiring...........................................5-100
Headlamps
Bulb Replacement.......................................5-50
Daytime Running Lamps...............................3-35
Exterior Lamps............................................3-32
Flash-to-Pass..............................................3-13
High Intensity Discharge (HID) Lighting...........5-50
High/Low Beam Changer................................ 3-9
On Reminder..............................................3-35
Wiper Activated...........................................3-35
Heated Seats................................................... 1-3
Heated Steering Wheel..................................... 3-7
Heater...........................................................3-42
Engine Coolant...........................................2-26
Highbeam On Light.........................................3-69
High-Speed Operation, Tires.............................5-62
Highway Hypnosis...........................................4-14
Hill and Mountain Roads..................................4-15
Hood
Checking Things Under................................5-12
Release.....................................................5-12
Horn ............................................................... 3-6
How to Wear Safety Belts Properly...................1-16
6