check engine CADILLAC DTS 2008 1.G Owner's Manual

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

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 3-65. 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.
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.
5-6

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 lift the hood, use the following steps:
1. Pull the hood release
lever with this symbol
on it. It is located
on the lower left side of
the instrument panel.
5-12

A. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-101.
B. Remote Positive (+) Terminal. SeeJump Starting on
page 5-42.
C. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-36.
D. Engine Coolant Surge Tank and Pressure Cap.
SeeCoolant Surge Tank Pressure Cap on page 5-27
andCooling System on page 5-30.
E. Remote Negative (−) Terminal. SeeJump Starting
on page 5-42.
F. Power Steering Fluid. SeePower Steering Fluid on
page 5-35.
G. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-15.
H. Engine Oil Dipstick. See “Checking Engine Oil”
underEngine Oil on page 5-15.
I. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-37.
J. Automatic Transmission Fluid Cap and Dipstick
(Out of View). SeeAutomatic Transmission Fluid
on page 5-21.
K. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-20.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.
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.
5-15

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.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 Driver
Information Center (DIC) will come on. 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 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 the last oil
change. Remember to reset the oil life system whenever
the oil is changed.
5-18

Follow these steps to reinstall the cover to the engine
air cleaner/lter housing:
1. Align the two hinges located on the inboard side of
the cover.
2. Push the cover slightly down and towards the
engine to engage the tabs in the hinges and
align the two screws.
3. Tighten the two screws on the top of the engine air
cleaner/lter housing cover.
{CAUTION:
Operating the engine with the air cleaner/lter
off can cause you or others to be burned.
The air cleaner not only cleans the air; it helps
to stop ames if the engine backres. If it is
not there and the engine backres, you could
be burned. Do not drive with it off, and be
careful working on the engine with the air
cleaner/lter off.Notice:If the air cleaner/lter is off, a backre can
cause a damaging engine re. And, dirt can easily get
into your engine, which will damage it. Always have
the air cleaner/lter in place when you are driving.
Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services on page 6-6, and be sure
to use the transmission uid listed inRecommended
Fluids and Lubricants on page 6-13.
5-21

How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission uid.Wait at least 30 minutes before checking the
transmission uid level if you have been driving:When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are
above 50°F (10°C). If it is colder than 50°F (10°C),
you may have to drive longer.
5-22

Checking the Fluid Level
Prepare you vehicle as follows:
1. Park your vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in PARK (P).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position
the shift lever in PARK (P).
4. Let the engine run at idle for three to ve minutes.
Then, without shutting off the engine, follow these steps:
The transmission uid cap is located next to the radiator
hose and below the engine air cleaner/lter assembly
on the driver’s side of the vehicle, and is marked
TRANS FLUID. SeeEngine Compartment Overview
on page 5-14for more information on location.
1. After removing the engine air cleaner/lter assembly
to reach the transmission uid cap, turn the cap
counterclockwise to remove. Pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds, and
then pull it back out again.3. Check both sides of the dipstick, and read the
lower level. The uid level must be in the
cross-hatched area.
4. If the uid level is in the acceptable range, push
the dipstick back in all the way and turn the
handle clockwise. Reinstall the engine air
cleaner/lter assembly.
5-23

How to Add Automatic Transmission
Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission uid to use. SeeRecommended
Fluids and Lubricants on page 6-13.
If the uid level is low, add only enough of the proper
uid to bring the level into the cross-hatched area on
the dipstick.
1. Pull out the dipstick.
2. Using a long-neck funnel, add enough uid at the
dipstick hole to bring it to the proper level.
It does not take much uid, generally less than
one pint (0.5 L). Do not overll.
Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-13.
3. After adding uid, recheck the uid level as
described under “How to Check Automatic
Transmission Fluid,” earlier in this section.
4. When the correct uid level is obtained, push the
dipstick back in all the way and turn the handle
clockwise.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, seeEngine Overheating
on page 5-27.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Giving freezing protection down to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as they
should.
Notice:Using coolant other than DEX-COOL
®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at the rst maintenance
service after each 30,000 miles (50 000 km) or
24 months, whichever occurs rst. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant in
the vehicle.
5-24

What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL®coolant which will not damage
aluminum parts. If you use this coolant mixture, you
do not need to add anything else.
{CAUTION:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but
would not get the overheat warning. The
engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:If an improper coolant mixture is used,
the engine could overheat and be badly damaged.
The repair cost would not be covered by the vehicle
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core,
and other parts.
If you have to add coolant more than two times a year,
have your dealer/retailer check your cooling system.
Notice:If extra inhibitors and/or additives are used
in the vehicle’s cooling system, the vehicle could
be damaged. Use only the proper mixture of
the engine coolant listed in this manual for the
cooling system. SeeRecommended Fluids and
Lubricants on page 6-13for more information.
5-25