2011 CADILLAC STS check engine

Black plate (62,1)Cadillac STS Owner Manual - 2011
Tire Pressure Light
For vehicles with a tire
pressure monitoring
system, this light comes
on briefly when the engine
is started. It provides
information about tire
pressures and the Tire
Pressure Monitoring
System.
When the Light is On Steady
This indicates that one or more of the tires is
significantly underinflated.
A tire pressure message in the Driver Information
Center (DIC), can accompany the light. SeeDriver
Information Center (DIC)
on page 4‑69for more
information. Stop and check the tires as soon as it is
safe to do so. If underinflated, inflate to the proper
pressure. See Inflation - Tire Pressure
on page 6‑58for more information.
When the Light Flashes First and Then is
On Steady
This indicates that there may be a problem with the Tire
Pressure Monitor System. The light flashes for about a
minute and stays on steady for the remainder of the
ignition cycle. This sequence repeats with every ignition
cycle. SeeTire Pressure Monitor Operation
on
page 6‑62for more information.
Malfunction Indicator Lamp
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation
of the fuel, ignition, and emission control systems.
It ensures that emissions are at acceptable levels for
the life of the vehicle, helping to produce a cleaner
environment.
4-62

Black plate (63,1)Cadillac STS Owner Manual - 2011
This light should come on
when the ignition is on,
but the engine is not
running, as a check to
show it is working. If it
does not, have the vehicle
serviced by your dealer.
If the check engine light comes on and stays on, while
the engine is running, this indicates that there is an
OBD II problem and service is required.
Malfunctions often are indicated by the system before
any problem is apparent. Being aware of the light can
prevent more serious damage to the vehicle. This
system assists the service technician in correctly
diagnosing any malfunction.
Notice: If the vehicle is continually driven with this
light on, after a while, the emission controls might
not work as well, the vehicle fuel economy might
not be as good, and the engine might not run as
smoothly. This could lead to costly repairs that
might not be covered by the vehicle warranty. Notice:
Modifications made to the engine,
transmission, exhaust, intake, or fuel system of the
vehicle or the replacement of the original tires with
other than those of the same Tire Performance
Criteria (TPC) can affect the vehicle's emission
controls and can cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by the vehicle warranty. This
could also result in a failure to pass a required
Emission Inspection/Maintenance test. See
Accessories and Modifications on page 6‑4.
This light comes on during a malfunction in one of
two ways:
Light Flashing: A misfire condition has been detected.
A misfire increases vehicle emissions and could
damage the emission control system on the vehicle.
Diagnosis and service might be required.
To prevent more serious damage to the vehicle:
.Reduce vehicle speed.
.Avoid hard accelerations.
.Avoid steep uphill grades.
.If towing a trailer, reduce the amount of cargo
being hauled as soon as it is possible.
4-63

Black plate (64,1)Cadillac STS Owner Manual - 2011
If the light continues to flash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the vehicle off, wait at least 10 seconds, and
restart the engine. If the light is still flashing, follow
the previous steps and see your dealer for service
as soon as possible.
Light On Steady:An emission control system
malfunction has been detected on the vehicle.
Diagnosis and service might be required.
An emission system malfunction might be corrected by
doing the following:
.Make sure the fuel cap is fully installed. See Filling
the Tankon page 6‑9. 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.
.If the vehicle has been driven through a deep
puddle of water, the 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.
.Make sure to fuel the vehicle with quality fuel.
Poor fuel quality causes the engine not to run as
efficiently as designed and can cause: stalling
after start-up, stalling when the vehicle is changed
into gear, misfiring, hesitation on acceleration,
or stumbling on acceleration. These conditions
might go away once the engine is warmed up.
If one or more of these conditions occurs, change
the fuel brand used. It will require at least one full
tank of the proper fuel to turn the light off.
See Gasoline Octane on page 6‑7.
If none of the above have made the light turn off,
your dealer can check the vehicle. The dealer has the
proper test equipment and diagnostic tools to fix any
mechanical or electrical problems that might have
developed.
4-64

Black plate (66,1)Cadillac STS Owner Manual - 2011
Oil Pressure Light
For vehicles with an oil
pressure light, if there is a
problem with the oil, the
light may stay on after
the engine is started,
or comes on while driving.
This light indicates that oil is not going through the
engine quickly enough to keep it lubricated. The engine
could be low on oil or could have some other oil
problem. Have the vehicle serviced by your dealer.
The oil light could also come on in the following
situations:
.The light comes on briefly when the ignition is
turned on to show that it is working properly. If it
does not come on with the ignition on, there may
be a problem with the fuse or bulb. Have the
vehicle serviced by your dealer.
.Sometimes when the engine is idling at a stop, a
chime sounds and the light may blink on and off.
This is normal.
{WARNING:
Do not keep driving if the oil pressure is low. The
engine can become so hot that it catches fire.
Someone could be burned. Check the oil as soon
as possible and have the vehicle serviced.
Notice: Lack of proper engine oil maintenance can
damage the engine. The repairs would not be
covered by the vehicle warranty. Always follow the
maintenance schedule for changing engine oil.
4-66

Black plate (78,1)Cadillac STS Owner Manual - 2011
BATTERY VOLTAGE LOW
This symbol appears
with this message.
This message displays when the electrical system is
charging less than 10 volts or the battery has been
drained.
If this message appears immediately after starting
the engine, it is possible that the generator can still
recharge the battery. The battery should recharge while
driving, but may take a few hours to do so. Consider
using an auxiliary charger to boost the battery after
returning home or to a final destination. Follow the
manufacturer's instructions.
If this message appears while driving or after starting
your vehicle and stays on, have it checked immediately
to determine the cause of this problem.
To help the generator recharge the battery quickly,
reduce the load on the electrical system by turning
off the accessories. The normal battery voltage range is 11.5 to 15.5 volts.
To monitor battery voltage on the DIC, press the
information button until BATTERY VOLTS displays.
CHANGE ENGINE OIL SOON
This message displays when the engine oil needs
to be changed. See your dealer. See
Engine Oilon
page 6‑16and Scheduled Maintenanceon page 7‑3for more information.
After resetting the CHANGE ENGINE OIL SOON
message by clearing it from the display, reset the
engine oil life system separately. For more information
on resetting the engine oil life system, see Engine Oil
Life System on page 6‑20.
CHECK BRAKE FLUID
This message displays if the ignition is on to inform the
driver that the brake fluid level is low. Have the brake
system serviced by your dealer as soon as possible.
See Brake System Warning Light
on page 4‑58for
more information.
CHECK GAS CAP
This message displays when the fuel cap has not been
fully tightened. Recheck the fuel cap to ensure that it is
on and tightened properly.
4-78

Black plate (5,1)Cadillac STS Owner Manual - 2011
Antilock Brake System (ABS)
This vehicle has the Antilock Brake System (ABS), an
advanced electronic braking system that helps prevent
a braking skid.
When the engine is started and the vehicle begins to
drive away, ABS checks itself. A momentary motor or
clicking noise might be heard while this test is going on,
and it might even be noticed that the brake pedal
moves a little. This is normal.
If there is a problem with
ABS, this warning light
stays on. SeeAntilock
Brake System (ABS)
Warning Light
on
page 4‑59.
Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:
A computer senses that the wheels are slowing down.
If one of the wheels is about to stop rolling, the
computer will separately work the brakes at each wheel. ABS can change the brake pressure to each wheel, as
required, faster than any driver could. This can help the
driver steer around the obstacle while braking hard.
As the brakes are applied, the computer keeps
receiving updates on wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change the time needed to
get a foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle in
front of you, there will not be enough time to apply the
brakes if that vehicle suddenly slows or stops. Always
leave enough room up ahead to stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down firmly and let antilock work. The antilock pump or
motor might be heard operating and the brake pedal
might be felt to pulsate , but this is normal.
5-5

Black plate (18,1)Cadillac STS Owner Manual - 2011
Before Leaving on a Long Trip
To prepare your vehicle for a long trip, consider having
it serviced by your dealer before departing.
Things to check on your own include:
.Windshield Washer Fluid:Reservoir full? Windows
clean —inside and outside?
.Wiper Blades: In good shape?
.Fuel, Engine Oil, Other Fluids: All levels checked?
.Lamps:Do they all work and are lenses clean?
.Tires:Are treads good? Are tires inflated to
recommended pressure?
.Weather and Maps: Safe to travel? Have
up-to-date maps?
Highway Hypnosis
Always be alert and pay attention to your surroundings
while driving. If you become tired or sleepy, find a safe
place to park your vehicle and rest.
Other driving tips include:
.Keep the vehicle well ventilated.
.Keep interior temperature cool.
.Keep your eyes moving —scan the road ahead
and to the sides.
.Check the rearview mirror and vehicle instruments
often.
5-18

Black plate (19,1)Cadillac STS Owner Manual - 2011
Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on flat or rolling terrain. Tips for driving in
these conditions include:
.Keep the vehicle serviced and in good shape.
.Check all fluid levels and brakes, tires, cooling
system, and transmission.
.Going down steep or long hills, shift to a
lower gear.
{WARNING:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{WARNING:
Coasting downhill in N (Neutral) or with the
ignition off is dangerous. The brakes will have to
do all the work of slowing down and they could
get so hot that they would not work well. You
would then have poor braking or even none going
down a hill. You could crash. Always have the
engine running and the vehicle in gear when
going downhill.
.Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds that
let you stay in your own lane.
.Top of hills: Be alert—something could be in your
lane (stalled car, accident).
.Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
5-19