2006 CADILLAC CTS check engine light

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of Your Vehicle...........................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Oil Life System..................................5-20
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Manual Transmission Fluid.............................5-24
Hydraulic Clutch...........................................5-25
Engine Coolant.............................................5-26
Coolant Surge Tank Pressure Cap..................5-28
Engine Overheating.......................................5-28Overheated Engine Protection
Operating Mode........................................5-30
Cooling System............................................5-31
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37
Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle.......................................................5-48
Headlamp Aiming...........................................5-49
Bulb Replacement..........................................5-52
High Intensity Discharge (HID) Lighting............5-52
Halogen Bulbs..............................................5-52
Front Turn Signal and Fog Lamps...................5-53
Taillamps, Turn Signal, Stoplamps and
Sidemarker Lamps.....................................5-53
Back-Up and License Plate Lamps..................5-54
Replacement Bulbs.......................................5-55
Windshield Wiper Blade Replacement..............5-55
Tires..............................................................5-57
Tire Sidewall Labeling...................................5-58
Tire Terminology and Denitions.....................5-61
Run-Flat Tires (CTS-V)..................................5-64
Ination - Tire Pressure.................................5-65
Tire Pressure Monitor System.........................5-68
Section 5 Service and Appearance Care
5-1

If your vehicle has the 6.0L V8 engine (VIN Code U),
use premium unleaded gasoline with a posted
octane rating of 91 or higher. You may also use regular
unleaded gasoline rated at 87 octane or higher, but
your vehicle’s acceleration may be slightly reduced,
and you may notice a slight audible knocking noise,
commonly referred to as spark knock. If the octane is
less than 87, you may 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 might damage your engine. If you are
using gasoline rated at 87 octane or higher and you
hear heavy knocking, your engine needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT).
General Motors recommends 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 may be affected. The malfunction
indicator lamp may turn on and your vehicle may fail
a smog-check test. SeeMalfunction Indicator Lamp
on page 3-41. If this occurs, return to your authorized
GM dealer for diagnosis. If it is determined that the
condition is caused by the type of fuel used, repairs
may not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. In most cases, you should not have to add
anything to your fuel. However, some gasolines contain
only the minimum amount of additive required to
meet U.S. Environmental Protection Agency regulations.
5-6

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, it means you need
to check the engine oil level right away. For more
information, see “Oil Pressure Low - Stop Engine”
underDIC Warnings and Messages on page 3-61and
Oil 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. See
Engine Compartment Overview on page 5-12for
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 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 message in the Driver Information
Center (DIC) will come on. Change your 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 may not indicate that an oil change
is necessary for over a year. However, your engine oil
and lter must be changed at least once a year and
at this time the system must be reset. Your dealer has
GM-trained service people who will perform this work
using genuine GM parts and reset the system. It is also
important to check your oil regularly and keep it at the
proper level.
If the system is ever reset accidentally, you must
change your 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.
How to Reset the Engine Oil Life
System and the Oil Life Indicator
The Engine Oil Life System calculates when to change
your engine oil and lter based on vehicle use. Anytime
your oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change your oil prior to a change engine oil
message in the DIC being turned on, reset the system.
After the oil has been changed, the change engine
oil message and the oil life indicator must be reset.
To reset the message and indicator, use one of
the following procedures:
Base Audio System
Press the CLR button located to the right of the DIC
display to acknowledge the change engine oil message.
This will clear the message from the display and reset it.
To reset the oil life indicator, use the following steps:
1. Press the up or down arrow on the INFO button
located to the right of the DIC display to access
the DIC menu.
2. Once XXX% ENGINE OIL LIFE menu item is
highlighted, press and hold the CLR button.
The percentage will return to 100, and the oil life
indicator will be reset. Repeat the steps if the
percentage does not return to 100.
3. Turn the key to OFF.
5-20

3. Fill the coolant surge tank with the proper mixture,
to slightly above the FULL COLD/FROID line on
the side of the coolant surge tank.4. With the coolant surge tank pressure cap off,
start the engine and let it run until you can feel
the upper radiator hose getting hot. The upper
radiator hose is the top hose coming out of
the radiator, on the passenger’s side of the
vehicle. Watch out for the engine cooling fans.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower,
add more of the proper mixture to the coolant surge
tank until the level reaches the FULL COLD/FROID
line on the side of the coolant surge tank.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Start the engine and allow it to warm up. If the
Check Coolant Level message does not appear on
the Driver Information Center (DIC), the coolant is at
the proper ll level. If a Check Coolant Level message
does appear, repeat Steps 1 to 3 then reinstall the
pressure cap, or see your dealer.
5-35

Brakes
Brake Fluid
Your brake master
cylinder reservoir is lled
with DOT-3 brake uid.
SeeEngine Compartment
Overview on page 5-12
for the location of the
reservoir.
There are only two reasons why the brake uid level
in the reservoir might go down. The rst is that the brake
uid goes down to an acceptable level during normal
brake lining wear. When new linings are put in, the uid
level goes back up. The other reason is that uid is
leaking out of the brake system. If it is, you should
have your brake system xed, since a leak means that
sooner or later your brakes will not work well, or will
not work at all.So, it is not a good idea to top off your brake uid.
Adding brake uid will not correct a leak. If you add uid
when your linings are worn, then you will have too
much uid when you get new brake linings. You should
add or remove brake uid, as necessary, only when
work is done on the brake hydraulic system.
{CAUTION:
If your vehicle has too much brake uid, it can
spill on the engine. The uid will burn if the
engine is hot enough. You or others could be
burned, and your vehicle could be damaged.
Add brake uid only when work is done on the
brake hydraulic system.
If the ignition is in ON and the brake uid is low, the
“Check Brake Fluid” message will be displayed in
the DIC. See “Check Brake Fluid Message” under
DIC Warnings and Messages on page 3-61.
When your brake uid falls to a low level, your brake
warning light will come on. SeeBrake System Warning
Light on page 3-38.
5-38

{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
Be sure the battery has enough water. You do
not need to add water to the battery installed
in your new vehicle. But if a battery has ller
caps, be sure the right amount of uid is there.
If it is low, add water to take care of that rst.
If you do not, explosive gas could be present.
Battery uid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, ush the place
with water and get medical help immediately.
{CAUTION:
Fans or other moving engine parts can injure
you badly. Keep your hands away from moving
parts once the engine is running.
5. Check that the jumper cables do not have loose
or missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) will go
to positive (+) or to a remote positive (+) terminal
if the vehicle has one. Negative (−) will go to a
heavy, unpainted metal engine part or to a remote
negative (−) terminal if the vehicle has one.
Do not connect positive (+) to negative (−)oryou
will get a short that would damage the battery
and maybe other parts too. And do not connect the
negative (−) cable to the negative (−) terminal on
the dead battery because this can cause sparks.
5-45

Electrical System
Add-On Electrical Equipment
Notice:Do not add anything electrical to your
vehicle unless you check with your dealer rst.
Some electrical equipment can damage your
vehicle and the damage would not be covered by
your warranty. Some add-on electrical equipment
can keep other components from working as
they should.
Add-on equipment can drain your vehicle’s battery,
even if your vehicle is not operating.
Your vehicle has an airbag system. Before attempting to
add anything electrical to your vehicle, seeServicing
Your Airbag-Equipped Vehicle on page 1-67.
Windshield Wiper Fuses
The windshield wiper motor is protected by an internal
circuit breaker. If the wiper motor overheats due to
heavy snow, the wipers will stop until the motor cools
and will then restart.
Power Windows and Other
Power Options
Circuit breakers protect the power windows and power
seats. When the current load is too heavy, the circuit
breaker opens and closes, protecting the circuit until the
problem is xed or goes away.
Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses and circuit
breakers. This greatly reduces the chance of res
caused by electrical problems.
Look at the silver-colored band inside the fuse. If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical
size and rating. If a fuse blows, see your dealer
for service immediately.
If you ever have a problem on the road and don’t
have a spare fuse, you can “borrow” one that has the
same amperage. Pick some feature of your vehicle that
you can get along without — like the radio or cigarette
lighter — and use its fuse, if it is the correct amperage.
Replace it as soon as you can.
The fuses are located in three fuse blocks, one located
in the engine compartment on the passenger’s side
and the other two under the rear seat.
5-104