2008 CADILLAC CTS check engine

Service............................................................5-4
Accessories and Modications..........................5-4
California Proposition 65 Warning.....................5-5
California Perchlorate Materials Requirements.....5-5
Doing Your Own Service Work.........................5-5
Adding Equipment to the Outside of the
Vehicle......................................................5-6
Fuel................................................................5-6
Gasoline Octane............................................5-7
Gasoline Specications....................................5-7
California Fuel...............................................5-7
Additives.......................................................5-8
Fuels in Foreign Countries...............................5-8
Filling the Tank..............................................5-9
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...................................................5-16
Engine Oil Life System..................................5-19
Engine Cover...............................................5-21
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-25
Manual Transmission Fluid.............................5-26Hydraulic Clutch...........................................5-27
Engine Coolant.............................................5-28
Coolant Surge Tank Pressure Cap..................5-31
Engine Overheating.......................................5-31
Overheated Engine Protection
Operating Mode........................................5-33
Cooling System............................................5-34
Power Steering Fluid.....................................5-39
Windshield Washer Fluid................................5-40
Brakes........................................................5-41
Battery........................................................5-44
Jump Starting...............................................5-45
All-Wheel Drive..............................................5-50
Rear Axle.......................................................5-51
Headlamp Aiming...........................................5-52
Bulb Replacement..........................................5-55
High Intensity Discharge (HID) Lighting............5-55
Halogen Bulbs..............................................5-55
Front Turn Signal and Fog Lamps...................5-56
License Plate Lamp......................................5-56
Replacement Bulbs.......................................5-57
Windshield Wiper Blade Replacement..............5-57
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 1-70.
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 6-18.
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.
The 8th digit of the Vehicle Identication Number (VIN)
shows the code letter or number that identies your
vehicle’s engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification Number
(VIN) on page 5-121.
5-6

Gasoline Octane
If your vehicle has the 3.6L V6 engine (VIN Code V),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you might notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this occurs,
use a gasoline rated at 87 octane or higher as soon as
possible. If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine needs
service.
If your vehicle has the 3.6L V6 engine (VIN Code 7),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. For best performance or trailer
towing, you could choose to use middle grade 89 octane
unleaded gasoline. If the octane rating is less than 87,
you might notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this occurs,
use a gasoline rated at 87 octane or higher as soon as
possible. 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 5-8
for 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 3-41. 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 the vehicle warranty.
5-7

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.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.
5-8

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.
5-12

A. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
B. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-123.
C. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
D. Remote Negative (+) Terminal. SeeJump Starting
on page 5-45.
E. Passenger Compartment Air Filter. SeePassenger
Compartment Air Filter on page 3-29.
F. Engine Cooling Fan. SeeCooling System on
page 5-34.
G. Power Steering Fluid Reservoir (Under Engine
Cover). SeePower Steering Fluid on page 5-39.H. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-16.
I. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-16.
J. Hydraulic Clutch Reservoir (If Equipped)
(Not Shown). See “When to Check and What
to Use” underHydraulic Clutch on page 5-27.
K. Brake Master Cylinder Reservoir (Out of View).
See “Brake Fluid” underBrakes on page 5-41.
L. Engine Coolant Surge Tank and Pressure Cap.
SeeCoolant Surge Tank Pressure Cap on page 5-31
andCooling System on page 5-34.
M. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
5-15

Engine Oil
There is an oil pressure
light in the instrument
cluster and an Oil Pressure
Low Stop Engine message
on the Driver Information
Center (DIC).
If the light and/or message appear, check the engine oil
level right away. For more information, see “Oil Pressure
Low Stop Engine” underDIC Warnings and Messages
on page 3-56andOil Pressure Light on page 3-44.
You should check the engine oil level regularly; this is
an added reminder.
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.
SeeEngine Compartment Overview on page 5-14
for 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.
5-16

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.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 will come on. See
DIC Warnings and Messages on page 3-56. 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.
5-19