2008 CADILLAC STS check engine

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 5-6for
additional information.
California Fuel
If your vehicle is certied to meet California Emissions
Standards, it is designed to operate on fuels that
meet California specications. See the underhood
emission control label. If this fuel is not available
in states adopting California emissions standards, your
vehicle will operate satisfactorily on fuels meeting
federal specications, but emission control system
performance might be affected. The malfunction
indicator lamp could turn on and your vehicle might fail
a smog-check test. SeeMalfunction Indicator Lamp
on page 3-68. If this occurs, return to your authorized
dealer/retailer for diagnosis. If it is determined that
the condition is caused by the type of fuel used, repairs
might not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In
most cases, you should not have to add anything to the
fuel. However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations. To help
keep fuel injectors and intake valves clean, or if
your vehicle experiences problems due to dirty injectors
or valves, look for gasoline that is advertised as TOP
TIER Detergent Gasoline. Also, your dealer/retailer has
additives that will help correct and prevent most
deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines might be available in
your area. We recommend that you use these gasolines,
if they comply with the specications described earlier.
However, E85 (85% ethanol) and other fuels containing
more than 10% ethanol must not be used in vehicles that
were not designed for those fuels.
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.
5-6

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.
Filling the Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Do not use cellular phones. Keep sparks,
ames, and smoking materials away from fuel.
Do not leave the fuel pump unattended when
refueling your vehicle. This is against the law
in some places. Do not re-enter the vehicle
while pumping fuel. Keep children away from
the fuel pump; never let children pump fuel.
5-7

Checking Things Under
the Hood
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing, and tools away
from any underhood electric fan.
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
Hood Release
To open the hood, do the following:
1. Pull the hood release
lever with this symbol
on it. It is located inside
the vehicle on the lower
left side of the
instrument panel.
5-10

After you have removed the sight shields (if equipped) on the 3.6L V6 engine, here is what you will see:
A. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-118.
B. Remote Negative (-) Terminal. SeeJump Starting on
page 5-45.
C. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
D. Battery. SeeBattery on page 5-44.
E. Passenger Compartment Air Filter. SeePassenger
Compartment Air Filter on page 3-55.
F. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.
G. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-18.H. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-18.
I. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.
J. Engine Coolant Surge Tank and Pressure Cap. See
Coolant Surge Tank Pressure Cap on page 5-29
andCooling System on page 5-32.
K. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-23.
L. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
5-13

After you have removed the sight shields (if equipped) on the 4.6L V8 engine, here is what you will see:
A. Remote Negative (-) Terminal. SeeJump Starting on
page 5-45.
B. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
C. Battery. SeeBattery on page 5-44.
D. Passenger Compartment Air Filter. SeePassenger
Compartment Air Filter on page 3-55.
E. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.
F. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-18.
G. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-18.H. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.
I. Engine Coolant Surge Tank and Pressure Cap. See
Coolant Surge Tank Pressure Cap on page 5-29
andCooling System on page 5-32.
J. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-23.
K. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-118.
L. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
5-15

After you have removed the sight shields (if equipped) on the 4.4L V8 STS-V engine, here is what you will see:
A. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-118.
B. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
C. Remote Negative (-) Terminal. SeeJump Starting on
page 5-45.
D. Battery. SeeBattery on page 5-44.
E. Passenger Compartment Air Filter. SeePassenger
Compartment Air Filter on page 3-55.
F. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
G. Intercooler System Pressure Cap. SeeEngine
Coolant on page 5-25.
H. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.
I. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-18.J. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-18.
K. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.
L. Engine Coolant Surge Tank and Pressure Cap. See
Coolant Surge Tank Pressure Cap on page 5-29
andCooling System on page 5-32.
M. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-23.
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.
5-17

Engine Oil
Checking Engine Oil
It is a good idea to check the engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-11for
the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
When to Add Engine Oil
V6 Engine
V8 Engine
5-18

Your vehicle’s engine is lled at the factory with a
Mobil 1®synthetic oil, which meets all requirements for
your vehicle.
Substitute Engine Oil: When adding oil to maintain
engine oil level, oil meeting GM Standard GM4718M
may not be available. You can add substitute oil
designated SAE 5W-30 with the starburst symbol at all
temperatures. Substitute oil not meeting GM Standard
GM4718M should not be used for an oil change.
Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the starburst symbol that meet GM standards are all
you need for good performance and engine protection.
Engine Oil Life System
When to Change Engine Oil
Your vehicle has a computer system that lets you know
when to change the engine oil and lter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.Notice:If your vehicle is an STS-V model, the
engine uses a special oil lter. The use of any other
engine oil lter could lead to lter failure and
result in severe engine damage. Damage caused by
use of the wrong engine oil lter would not be
covered by your new vehicle warranty.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL SOON message in
the DIC will come on. SeeDIC Warnings and Messages
on page 3-80. Change the oil as soon as possible
within the next 600 miles (1 000 km). It is possible that,
if you are driving under the best conditions, the oil
life system might not indicate that an oil change
is necessary for over a year. However, the engine oil
and lter must be changed at least once a year and at
this time the system must be reset. Your dealer/retailer
has trained service people who will perform this
work using genuine parts and reset the system. It is
also important to check the oil regularly and keep it at
the proper level.
If the system is ever reset accidentally, you must
change the oil at 3,000 miles (5 000 km) since your last
oil change. Remember to reset the oil life system
whenever the oil is changed.
5-21