2007 GMC YUKON XL engine

Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages
on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that
something is wrong before it becomes serious
enough to cause an expensive repair or
replacement. Paying attention to your warning
lights and gages could also save you or others
from injury.
Warning lights come on when there may be or is
a problem with one of your vehicle’s functions.
As you will see in the details on the next few
pages, some warning lights come on briey when
you start the engine just to let you know they
are working. If you are familiar with this section,
you should not be alarmed when this happens.Gages can indicate when there may be or is a
problem with one of your vehicle’s functions.
Often gages and warning lights work together to
let you know when there is a problem with
your vehicle.
When one of the warning lights comes on and
stays on when you are driving, or when one of the
gages shows there may be a problem, check
the section that tells you what to do about
it. Please follow this manual’s advice. Waiting to
do repairs can be costly – and even dangerous.
So please get to know your warning lights
and gages. They are a big help.
Your vehicle also has a Driver Information Center
(DIC) that works along with warning lights and
gages. SeeDIC Warnings and Messages
on page 254.
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Speedometer and Odometer
Your speedometer lets you see your speed in both
miles per hour (mph) and kilometers per hour
(km/h). Your odometer shows how far your vehicle
has been driven, in either miles (used in the
United States) or kilometers (used in Canada).
Trip Odometer
The trip odometer can tell you how far your vehicle
has been driven since you last set the trip odometer
to zero.
Press the reset button, located on the instrument
panel cluster next to the trip odometer display,
to toggle between the trip odometer and the
regular odometer. Holding the reset button for
approximately one second while the trip odometer
is displayed will reset it.
To display the odometer reading with the ignition
off, press the reset button.
Tachometer
Your tachometer displays the engine speed in
revolutions per minute (rpm).
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime
will be provided for several seconds to remind
people to buckle their safety belts. The driver safety
belt light will also be provided and stay on for
several seconds, then it will ash for several more.
You should buckle your seat belt.
This chime and light will
be repeated if the driver
remains unbuckled
and the vehicle
is in motion.
If the driver’s belt is buckled, neither the chime nor
the light will come on.
SeePassenger Sensing System on page 100for
more information.
226

If, after several seconds, all 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 for service.
{CAUTION:
If the off indicator and the airbag
readiness light ever come on together, it
means that something may be wrong with
the airbag system. If this ever happens,
have the vehicle serviced promptly,
because an adult-size person sitting in the
right front passenger seat may not have
the protection of the frontal airbag. See
Airbag Readiness Light on page 227.
Charging System Light
The charging system
light will come on briey
when you turn on the
ignition, but the
engine is not running,
as a check to show you
it is working.
It should go out once the engine is running.
If it stays on, or comes on while you are driving,
you may have a problem with the charging system.
It could indicate that you have problems with the
generator, the generator drive belt, or another
electrical problem. Have it checked right away.
Driving while this light is on could drain your
battery.
When this light comes on, the DIC will also display
the SERVICE BATTERY NOT CHARGING
SYSTEM message. SeeDIC Warnings and
Messages on page 254for more information.
If you must drive a short distance with the light on,
be certain to turn off all your accessories, such as
the radio and air conditioner, to reduce the drain on
your battery.
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Voltmeter Gage
When your engine is not
running, but the ignition
is in RUN, this gage
shows your 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.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.
SeeDIC Warnings and Messages on page 254
andCharging System Light on page 230for more
information.
231

Anti-Lock Brake System Warning
Light
With the anti-lock brake
system, this light will
come on when you start
your engine and may
stay on for several
seconds.
That’s normal. If the light does not come on then,
have it xed so it will be ready to warn you if
there is a problem.If the light stays on, or comes on when you are
driving, your vehicle needs service. You will
also hear a chime sound when the light is on
steady. If the regular brake system warning light is
not on, you still have brakes, but you do not
have anti-lock brakes. If the regular brake system
warning light is also on you do not have anti-lock
brakes and there is a problem with your regular
brakes. In addition to both lights, you will also hear
a chime sound on the rst occurrence of a
problem and each time the vehicle is shut off and
then restarted. SeeBrake System Warning
Light on page 232.
The anti-lock brake system warning light should
come on briey when you turn the ignition
key to RUN. If the light does not come on then,
have it xed so it will be ready to warn you if there
is a problem.
233

StabiliTrak®Indicator Light
If equipped, this warning
light should come on
briey when the engine
is started.
If the warning light does not come on then, have it
xed so it will be ready to warn you if there is a
problem. If it stays on, or comes on when you are
driving, there may be a problem with your
StabiliTrak
®system and your vehicle may need
service. When this warning light is on, the system
is off and will not limit wheel spin. Adjust your
driving accordingly.
This light will also ash when the StabiliTrak
®
system is active.
If the StabiliTrak
®system warning light comes on
and stays on for an extended period of time
when the system is turned on, your vehicle needs
service. SeeStabiliTrak
®System on page 348
for more information.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your
vehicle is working. During a majority of the
operation, the gage will read 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 452.
United StatesCanada
234

Malfunction Indicator Lamp
Check Engine Light
Your vehicle has a
computer which
monitors operation of
the fuel, ignition,
and emission control
systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended
to assure that emissions are at acceptable
levels for the life of the vehicle, helping to produce
a cleaner environment. The check engine light
comes on to indicate that there is a problem and
service is required. Malfunctions often will be
indicated by the system before any problem is
apparent. This may prevent more serious damage
to your vehicle. This system is also designed to
assist your service technician in correctly
diagnosing any malfunction.Notice:If you keep driving your vehicle with
this light on, after awhile, your emission
controls may not work as well, your fuel
economy may not be as good, and your engine
may not run as smoothly. This could lead to
costly repairs that may not be covered by your
warranty.
Notice:Modications made to the engine,
transmission, exhaust, intake, or fuel system
of your vehicle or the replacement of the
original tires with other than those of the same
Tire Performance Criteria (TPC) can affect
your vehicle’s emission controls and may
cause this light to come on. Modications to
these systems could lead to costly repairs not
covered by your warranty. This may also
result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 426.
236

This light should come on, as a check to show
you it is working, when the ignition is on and the
engine is not running. If the light does not
come on, have it repaired. This light will also
come on during a malfunction in one of two ways:
Light Flashing— A misre condition has
been detected. A misre increases vehicle
emissions and may damage the emission
control system on your vehicle. Diagnosis and
service may be required.
Light On Steady— An emission control
system malfunction has been detected on your
vehicle. Diagnosis and service may be
required.
If the Light is Flashing
The following may prevent more serious damage
to your vehicle:
Reducing vehicle speed
Avoiding hard accelerations
Avoiding steep uphill grades
If you are towing a trailer, reduce the amount
of cargo being hauled as soon as it is
possible
If the light stops ashing and remains on steady,
see “If the Light Is On Steady” following.
If the light continues to ash, when it is safe to do
so, stop the vehicle. Find a safe place to park
your vehicle. Turn the key off, wait at least
10 seconds and restart the engine. If the light
remains on steady, see “If the Light Is On Steady”
following. If the light is still ashing, follow the
previous steps, and see your dealer for service as
soon as possible.
237