2009 GMC YUKON Owner's Manual

If, after several seconds, both status indicator lights
remain on, or if there are no lights at all, there may be a
problem with the lights or the passenger sensing
system. See your dealer/retailer for service.
{CAUTION:
If the airbag readiness light ever comes on and
stays on, it means that something may be wrong
with the airbag system. To help avoid injury to
yourself or others, have the vehicle serviced right
away. SeeAirbag Readiness Light on page 3-37
for more information, including important safety
information.
Charging System Light
This light comes on briey
when the ignition key is
turned to START, 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/retailer.
The light should go out once the engine starts. If it stays
on, or comes on while driving, there could be a problem
with the charging system. A charging system message in
the Driver Information Center (DIC) can also appear. See
DIC Warnings and Messages on page 3-64for more
information. This light could indicate that there are
problems with a generator drive belt, or that there is an
electrical problem. Have it checked right away. If the
vehicle must be driven a short distance with the light on,
turn off accessories, such as the radio and air
conditioner.
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Voltmeter Gage
When the engine is not
running, but the ignition is
on, this gage shows
the battery’s state of
charge in DC volts.
When the engine is running, the gage shows the
condition of the charging system. The charging system
regulates voltage based on the state of the battery
for improved fuel economy and battery life. The gage
may transition from a higher to lower or a lower to higher
reading, this is normal. Readings between the low
and high warning zones indicate the normal operating
range. The gage may also read low during the fuel
economy mode, this is normal.Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power
at engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create full power. If
there is a problem with the battery charging system, this
light will come on or the SERVICE BATTERY
CHARGING SYSTEM DIC message will display. See
DIC Warnings and Messages on page 3-64and
Charging System Light on page 3-39for more
information.
Brake System Warning Light
With the ignition on, the brake system warning light
comes on when the parking brake is set. If the vehicle is
driven with the parking brake engaged, a chime sounds
when the vehicle speed is greater than 5 mph (8 km/h).
The vehicle’s hydraulic brake system is divided into
two parts. If one part is not working, the other part can
still work and stop the vehicle. For good braking,
both parts need to be working well.
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If the warning light comes on and a chime sounds there
could be a brake problem. Have the brake system
inspected right away.
This light can also come on due to low brake uid. See
Brakes on page 5-41for more information.
This light comes on briey when the ignition key is
turned to ON/RUN. If it does not come on then, have it
xed so it is ready to warn if there is a problem.
{CAUTION:
The brake system might not be working properly if
the brake system warning light is on. Driving with
the brake system warning light on can lead to a
crash. If the light is still on after the vehicle has
been pulled off the road and carefully stopped,
have the vehicle towed for service.
If the light comes on while driving, pull off the road and
stop carefully. The pedal might be harder to push or
might go closer to the oor. It can take longer to stop.
If the light is still on, have the vehicle towed for service.
SeeTowing Your Vehicle on page 4-44. United States
Canada
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Antilock Brake System (ABS)
Warning Light
For vehicles with the
Antilock Brake System
(ABS), this light comes on
briey when the engine
is started.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light then goes off.
If the ABS light stays on, turn the ignition off. If the light
comes on while driving, stop as soon as it is safely
possible and turn the ignition off. Then start the engine
again to reset the system. If the ABS light stays on, or
comes on again while driving, the vehicle needs service.
If the regular brake system warning light is not on, the
vehicle still has brakes, but not antilock brakes. If the
regular brake system warning light is also on, the vehicle
does not have antilock brakes and there is a problem with
the regular brakes. SeeBrake System Warning Light on
page 3-40.
For vehicles with a Driver Information Center (DIC), see
DIC Warnings and Messages on page 3-64for all
brake related DIC messages.
StabiliTrak®Indicator Light
For vehicles with the
StabiliTrak®system, this
light comes on briey while
starting the engine.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light then goes off.
If the light comes on and stays on while driving, there
could be a problem with the StabiliTrak
®system and the
vehicle might need service. When this warning light is
on, the StabiliTrak
®system is off and does not limit
wheel spin.
The light ashes if the system is active and is working
to assist the driver with directional control of the
vehicle in difficult driving conditions.
SeeStabiliTrak
®System on page 4-6for more
information.
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Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard the vehicle is
working. During a majority of the operation, the gage
reads 210°F (100°C) or less. If you are pulling a load or
going up hills, it is normal for the temperature to uctuate
and approach the 250°F (122°C) mark. If the gage
reaches the 260°F (125°C) mark, it indicates that the
cooling system is working beyond its capacity.
SeeEngine Overheating on page 5-35.
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Tire Pressure Light
For vehicles with a tire
pressure light, this light
comes on briey when
the engine is started and
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 signicantly
underinated.
A tire pressure message in the Driver Information
Center (DIC), can accompany the light. SeeDIC
Warnings and Messages on page 3-64for more
information. Stop and check the tires as soon as it is
safe to do so. If a tire is underinated, inate to the
proper pressure. SeeTires on page 5-62for more
information. United StatesCanada
3-43

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 5-72
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
ensures that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment.
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/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.
3-44

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.
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.
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 5-9. 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,
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.
3-45

If none of the above have made the light turn off, your
dealer/retailer can check the vehicle. The dealer/retailer
has the proper test equipment and diagnostic tools to x
any mechanical or electrical problems that might have
developed.
Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
might begin programs to inspect the emission control
equipment on the vehicle. Failure to pass this inspection
could prevent getting a vehicle registration.
Here are some things to know to help the vehicle pass
an inspection:
The vehicle will not pass this inspection if the check
engine light is on with the engine running, or if the
key is in ON/RUN and the light is not on.
The vehicle will not pass this inspection if the OBD II
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen
if the battery has recently been replaced or if the
battery has run down. The diagnostic system is
designed to evaluate critical emission controlsystems during normal driving. This can take several
days of routine driving. If this has been done and the
vehicle still does not pass the inspection for lack of
OBD II system readiness, your dealer/retailer can
prepare the vehicle for inspection.
Oil Pressure Gage
The oil pressure gage shows the engine oil pressure
in psi (pounds per square inch) when the engine
is running. Canadian vehicles indicate pressure in
kPa (kilopascals).United States
Canada
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