2009 CADILLAC STS service

Lane Departure Warning Light
For vehicles with the lane
departure warning system,
this light briey comes
on green, while starting
the vehicle, to indicate
that it is working.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light will then go off.
This light also comes on green if the system detects a
left or right lane marking. It ashes, changes to amber
and three beeps sound if a detected lane marking is
crossed without using a turn signal. For more information,
see the Index in the Navigation Manual.
Engine Coolant Temperature
Warning Light
The engine coolant
temperature warning
light comes on when
the engine is very hot.
This light also comes on briey when the vehicle is
started.
If the light does not go out or comes on and stays on
while driving, there may be a problem with the cooling
system. Driving with engine coolant temperature light on
could cause the vehicle to overheat, seeOverheated
Engine Protection Operating Mode on page 5-36.
SeeEngine Overheating on page 5-34andDIC
Warnings and Messages on page 3-79for more
information.
3-64

When the Light Flashes First and Then is
On Steady
This indicates that there could be a problem with the
Tire Pressure Monitor System. The light ashes 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 System on page 5-66
for more information.
Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation of
the fuel, ignition, and emission control systems. It makes
sure that emissions are at acceptable levels for the life of
the vehicle, helping to produce a cleaner environment.
This comes on briey
while starting the engine.
If it does not come on, have
the vehicle serviced by your
dealer/retailer.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’s 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:Modications 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.
Modications 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 5-3.
3-66

This light comes on during a malfunction in one of
two ways:
Light Flashing:A misre condition has been detected.
A misre increases vehicle emissions and could damage
the emission control system on the vehicle. Diagnosis
and service might be required.
The following can prevent more serious damage to the
vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid steep uphill grades.
If the light continues to ash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the key off, wait at least 10 seconds, and restart
the engine. If the light is still ashing, follow the previous
steps and see your dealer/retailer 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. SeeFilling
the Tank on page 5-8. 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 may cause: stalling after start-up,
stalling when the vehicle is changed into gear,
misring, 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.
SeeGasoline Octane on page 5-5.
3-67

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 it xed right away.
The oil light could also come on in the following
situations:
The light comes on briey 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
it xed right away.
Sometimes when the engine is idling at a stop, a
chime sounds and the light may blink on and off.
This is normal.
{CAUTION:
Do not keep driving if the oil pressure is low.
The engine can become so hot that it catches re.
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 in this manual for
changing engine oil.
Security Light
For information regarding
this light and the vehicle’s
security system, see
Theft-Deterrent System
on page 2-21.
3-69

Tire Pressure
This display shows the pressure for each tire in either
pounds per square inch (psi) or kilopascals (kPa). If the
tire pressure is normal, the value will display. If the tire
pressure is low or high, LOW or HIGH will appear on
the display with the value. SeeInflation - Tire Pressure
on page 5-64andDIC Warnings and Messages on
page 3-79for more information. Press the information
button to scroll through the following displays:
LF TIRE:This display shows the pressure in the driver
side front tire.
RF TIRE:This display shows the pressure in the
passenger side front tire.
LR TIRE:This display shows the pressure in the driver
side rear tire.
RR TIRE:This display shows the pressure in the
passenger side rear tire.
If the tire pressure display shows dashes instead of
a value, there may be a problem with your vehicle. If this
consistently occurs, see your dealer/retailer for service.
ENGINE OIL LIFE
If your vehicle has this display, it shows the estimated
oil life remaining. If you see 99% ENGINE OIL LIFE
on the display, that means that 99% of the current oil
life remains.
When the oil life is depleted, the CHANGE ENGINE OIL
SOON message will appear on the display. Change
the oil as soon as possible. In addition to the engine oil
life system monitoring the oil life, additional maintenance
is recommended in the Maintenance Schedule in this
manual. SeeScheduled Maintenance on page 6-4
andEngine Oil on page 5-18.
After an oil change, reset the ENGINE OIL LIFE display.
To reset, seeEngine Oil Life System on page 5-21.
The display will show 100% ENGINE OIL LIFE after
it has been reset. Also clear the CHANGE ENGINE OIL
SOON message from the display.
ENGLISH DISPLAY UNITS
(METRIC DISPLAY UNITS)
This display allows you to select between English and
metric units of measurement if your vehicle has the
uplevel DIC. Press the reset button to switch between
English and metric units.
Blank Line
This display shows no information.
3-77

BATTERY NOT CHARGING SERVICE
CHARGING SYS (System)
This symbol appears with
this message.
This message displays when a problem with the
charging system has been detected. Have your
vehicle serviced by your dealer/retailer.
BATTERY SAVER ACTIVE
This message displays when the system detects that the
battery voltage is dropping beyond a reasonable level.
The battery saver system starts reducing certain features
of the vehicle that may be noticeable. At the point that
the features are disabled, this message is displayed.
It means that the vehicle is trying to save the charge
in the battery.
Turn off all unnecessary accessories to allow the battery
to recharge.
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.
BATTERY VOLTAGE HIGH
This symbol appears with
this message.
This message displays when the electrical charging
system is overcharging the battery. When the system
detects that the battery voltage is above an estimated
16 volts, this message displays.
To reduce the charging overload, use the vehicle’s
accessories:
Turn on the exterior lamps and radio.
Set the climate control on AUTO and the fan speed
on the highest setting.
Turn the rear window defogger on.
The normal battery voltage range is 11.5 to 15.5 volts
when the engine is running. To monitor battery voltage
on the DIC, press the information button until
BATTERY VOLTS displays.
3-80

CHECK BRAKE FLUID
This message displays if the ignition is on to inform the
driver that the brake uid level is low. Have the brake
system serviced by your dealer/retailer as soon as
possible. SeeBrake System Warning Light on page 3-62
for 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.
CHECK TIRE PRESSURE
This message displays when the pressure in one or
more of the vehicle’s tires needs to be checked. If a tire
pressure message appears on the DIC, stop as soon as
you can. Have the tire pressures checked and set to
those shown on the Tire Loading Information label. See
Tires on page 5-54,Loading the Vehicle on page 4-24,
andInflation - Tire Pressure on page 5-64. The DIC also
shows the tire pressure values. SeeDIC Operation and
Displays on page 3-72. If the tire pressure is low, the low
tire pressure warning light comes on. SeeTire Pressure
Light on page 3-65.
CHECK WASHER FLUID
This symbol appears with
this message.
This message displays when the windshield washer
uid is low. Fill the windshield washer uid reservoir
as soon as possible. SeeWindshield Washer Fluid
on page 5-38for more information.
CLEAN RADAR
This message displays when the Adaptive Cruise
Control system is disabled because the radar is blocked
and cannot detect vehicles in your path. It may also
activate during heavy rain or due to road spray. To clean
the system, see “Cleaning the System” underAdaptive
Cruise Control on page 3-20.
3-82

ENGINE HOT – AC
(Air Conditioning) OFF
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
SeeEngine Coolant Temperature Gage on page 3-65.
To avoid added strain on a hot engine, the air
conditioning compressor is automatically turned off.
When the coolant temperature returns to normal, the
air conditioning compressor turns back on. You can
continue to drive your vehicle.
If this message continues to appear, have the system
repaired by your dealer/retailer as soon as possible
to avoid damage to the engine.
ENGINE POWER REDUCED
This message displays when the engine power is being
reduced to protect the engine from damage. There could
be several malfunctions that might cause this message.
Reduced engine power can affect the vehicle’s ability to
accelerate. If this message is on, but there is no reduction
in performance, proceed to your destination. The
performance may be reduced the next time the vehicle
is driven. The vehicle may be driven at a reduced speed
while this message is on, but acceleration and speed may
be reduced. Anytime this message stays on, take the
vehicle to your dealer/retailer for service as soon as
possible.
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