engine GMC YUKON 2007 Owner's Guide

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 252.
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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 vehicle’s odometer works together with the
driver information center. You can set a Trip A and
Trip B odometer. See “Trip Information” under
DIC Operation and Displays (Using DIC Buttons)
on page 245orDIC Operation and Displays
(Using Trip Odometer Reset Stem) on page 250.
The odometer mileage can be checked without
the vehicle running. Simply press the trip stem on
the instrument panel cluster.
If your vehicle ever needs a new odometer
installed, the new one will be set to the correct
mileage total of the old odometer.
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).
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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 a
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 battery not charging message. SeeDIC
Warnings and Messages on page 252.
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.
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 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.
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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 maximum power.
You can only drive for a short time with the
reading in either warning zone. If you must drive,
turn off all unnecessary accessories.
Readings in either warning zone indicate a
possible problem in the electrical system. Have
the vehicle serviced as soon as possible.Brake System Warning Light
With the ignition on, the brake system warning
light will come on when you set the parking brake.
If you try to drive with the parking brake engaged,
a chime will sound when the vehicle speed is
greater than 3 mph (5 km/h).
Your vehicle’s hydraulic brake system is divided
into two parts. If one part is not working, the other
part can still work and stop you. For good
braking, though, you need both parts working well.
If the warning light comes on and a chime
sounds there could be a brake problem. Have
your brake system inspected right away.
This light may also come on due to low brake
uid. SeeBrakes on page 459for more
information.
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This light should come on briey when you turn
the ignition key to RUN. If it does not come
on then, have it xed so it will be ready to warn
you if there’s a problem.
If the light comes on while you are driving, pull off
the road and stop carefully. You may notice
that the pedal is harder to push or may go closer
to the oor. It may take longer to stop. If the
light is still on, have the vehicle towed for service.
SeeTowing Your Vehicle on page 398.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light
is on. Driving with the brake system
warning light on can lead to an accident.
If the light is still on after you have pulled
off the road and stopped carefully, have
the vehicle towed for service.
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.
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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 233.
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.StabiliTrak®Indicator Light
For vehicles equipped
with the StabiliTrak®
system, 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
will not limit wheel spin. Adjust your driving
accordingly.
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 349
for 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 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 448.
Tire Pressure Light
If your vehicle is
equipped with the Tire
Pressure Monitor
system, this light will
come on if the system
detects low tire
pressure.
A CHECK TIRE PRESSURE DIC message will
accompany the light.
This light will also come on briey as you start the
engine.
SeeTire Pressure Monitor System on page 490
for more information.
For more information on your tires, seeTires on
page 480.
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236

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 421.
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.
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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
possibleIf 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.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully
install the cap. SeeFilling the Tank on page 426.
The diagnostic system can determine if the fuel cap
has been left off or improperly installed. A loose or
missing fuel cap will allow fuel to evaporate into the
atmosphere. A few driving trips with the cap
properly installed should turn the light off.
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Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The
condition will usually be corrected when the
electrical system dries out. A few driving trips
should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
SeeGasoline Octane on page 423. Poor fuel
quality will cause your engine not to run as
efficiently as designed. You may notice this as
stalling after start-up, stalling when you put
the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration. (These
conditions may go away once the engine is
warmed up.) This will be detected by the system
and cause the light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at
least one full tank of the proper fuel to turn the
light off.
If none of the above steps have made the light
turn off, your dealer can check the vehicle.
Your dealer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that may have developed.Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have
or may begin programs to inspect the emission
control equipment on your vehicle. Failure to pass
this inspection could prevent you from getting a
vehicle registration.
Here are some things you need to know to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the
check engine light is on or not working properly.
Your vehicle will not pass this inspection if
the OBD (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 you have recently
replaced your battery or if your battery has
run down. The diagnostic system is designed to
evaluate critical emission control systems
during normal driving. This may take several days
of routine driving. If you have done this and
your vehicle still does not pass the inspection for
lack of OBD system readiness, your GM dealer
can prepare the vehicle for inspection.
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