2003 GMC YUKON DENALI light

Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag’s electrical system for malfunctions.
The light tells you
if there is an electrical problem.
The system check includes the air bag sensors, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, see
Air Bag Systems on page 1-72.
This light will come on
when you start your
vehicle, and it will flash for
a few seconds. Then
the light should go out.
This means the system
is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air
bag system may not work properly. Have your vehicle
serviced right away.
16 the air bag readiness light stays on after yscl
start your vehicle,
it means the air bag system
may not be working properly. The air bags
in
your vehicle may not inflate in a crash, or they could even inflate without a crash.
To help
avoid injury to yourself or others, have your
vehicle serviced right away
if the air bag
readiness light stays on after you start your
vehicle.
The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN. If the
light doesn’t come on then, have it fixed
so it will
be ready to warn you
if there is a problem.
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Passenger Air Bag Status Indicator as a system check. Then, after several more seconds,
the status indicator will light either
ON or OFF, or
If your vehicle has the passenger sensing system either the on or off symbol to let you know the status of
your rearview mirror Will have a passenger air bag status the right front passenger’s frontal air bag.
indicator.
Passenger Air Bag Status Indicator
- United States
If the word ON or the on symbol is lit on the passenger
air bag status indicator, it means that the right front
passenger’s frontal air bag is en, ed (may inflate).
Passenger Air Bag Status Indicator
- Canada
When the ignition key is turned
to RUN or START, the
passenger air bag status indicator will light
ON and
OFF, or the symbol for on and off, for several seconds
.. le on inc ator comes on when you have a
rear-facing child restraint installed in the right
front passenger’s seat,
it means that the
passenger sensing system has not turned
off
the passenger’s frontal air bag. A child in a
rear-facing child restraint can be seriously
injured or killed
if the right front passenger’s
air bag inflates. This is because the back of
the rear-facing child restraint would be very close to the inflating air bag. Don’t use a
rear-facing child restraint
in the right front
passenger’s seat unless the air bag has been
turned
off.
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If the word OFF or the off symbol is lit on the air bag
status indicator,
it means that the passenger sensing
system has turned
off the right front passenger’s frontal
air bag. See Passenger Sensing System on page
7 -8 7
for more on this, including important safety information.
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.
__ -he ofl ..jdicator and the air bag readiness
light ever come on together, it means that
something may be wrong with the air bag
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 air
bag. See “Air Bag Readiness Light” in the
Index.
Charging System Light
The charging system light
will come on briefly 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. See
DIC Warnings
and Messages
on page 3-52.
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.
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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. 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 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
flash when you set the parking brake. The light will
flash
if the parking brake doesn’t release fully. 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 isn’t 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.
3-34

w,
United States Canada
This light should come on briefly when you turn the
ignition key to
RUN. If it doesn’t come on then, have it
fixed
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, the pedal may go closer to the
floor.
It may take longer to stop. If the light is still on,
have
the vehicle towed for service. See Towing
Your Vehicle on page 4-44.
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’ve 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.
That’s normal. If the light doesn’t come on then, have
it
fixed so it will be ready to warn you if there is a
problem.
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If the light stays on, or comes on when you’re 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 isn’t on, you still have
brakes, but you don’t have anti-lock brakes.
If the
regular brake system warning light is also on you don’t
have anti-lock brakes and there’s a problem with
your regular brakes. In addition to both lights, you will
also hear a chime sound on the first occurrence of
a problem and each time the car is shut off and then
restarted. See Brake System Warning Light on
page
3-34.
Traction Off Light
If you have the
Stabilitrak@system, this
light should come on briefly
when you turn the
ignition to
RUN.
If the light doesn’t come on then, the system may
require service; have it fixed
so it will be there to warn
you
if the system is turned off.
For more information on the traction off light, see
Stabilitrak@
System on page 4-9.
3-36
Engine Coolant Temperature Gage
~~ ~
United States
I I
Canada
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 21
0°F (100°C) or less. If you are pulling a load
or going up hills, it is normal for the temperature to
fluctuate 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.
See Engine Overheating on page
5-25.

A temporary solution to hotter transmission operating
temperatures may be
to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, see
Scheduled Maintenance
on page
6-5 for the proper transmission maintenance
intervals.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with
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 a while, 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: Modifications 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.
Modifications 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.
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 doesn’t come on, have it
repaired. This light will also come on during
a
malfunction in one of two ways:
Light Flashing - A misfire condition has been
detected.
A misfire increases vehicle emissions
and may damage the emission control system on
your vehicle. Dealer or qualified service center
diagnosis and service may be required.
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Light On Steady - An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center 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 flashing and remains on steady, see “If
the Light
Is On Steady” following.
If the light continues to flash, 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
flashing, follow the previous steps, and drive the vehicle
to your dealer or qualified service center for service.
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. See Filling
Your Tank on page 5-7. 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.
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. See
Gasoline Octane
on page 5-5. 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, misfiring, 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.