2003 GMC YUKON DENALI service

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.

If none of the above steps have made the light turn off,
have your dealer or qualified service center check
the vehicle. Your dealer has the proper test equipment
and diagnostic
tools to fix any mechanical or electrical
problems that may have developed.
€missions 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, see your dealer or qualified service
center to prepare the vehicle for inspection.
Oil Pressure Gage
_I
United States Canada
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).
Oil pressure may vary with engine speed, outside
temperature and
oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
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A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem
causing
low oil pressure. Check your oil as soon as
possible. See
Engine Oil on page 5-13.
DL.. t kc-> dl - - jng if -..3 oil pressure is IOL- If
you do, your engine can become
so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice: Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
Security Light
1 This light will come on
I'
brieflywhen you turn the
key toward START.
The light will stay on until
the engine starts.
If the light flashes, the Passlock@ system has entered a
tamper mode. If the vehicle fails
to start, see Passlock@
on page
2- 17.
If the iight comes on continuously while driving and
stays on, there may be a problem with the Passlock@
system. Your vehicle will not be protected by Passlock@,
and you should see your dealer.
Also, see Content Theft-Deterrent on page 2- 16 for
additional information regarding the security light.
Cruise Control Light
The cruise light comes on
whenever you
set your
cruise control. See Cruise
Control under Turn
SignaVMultifunction Lever
on page 3-7.
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Driver Information Center (DIC)
The DIC display is located on the instrument panel
cluster above the steering wheel. The DIC can display
information such as the trip odometer, fuel economy and
personalization features.
A (Trip Information): This button will display the
odometer, personal trip odometer, business trip
odometer, hourmeter, annual log and the timer.
B (Fuel Information): This button will display the
current range, average fuel economy, instant fuel
economy and engine oil life.
C (Personalization): This button will change personal
options available on your vehicle.
D (Select): This button resets certain functions and
turns off
or acknowledges nessages on the DIC.
DIC Operation and Displays
The DIC comes on when the ignition is on. After a short
delay the DIC will display the current driver
(1 or 2)
and the information that was last displayed before the
engine was turned off.
If a problem is detected, a warning message will appear
on the display. Pressing any of the four buttons will
acknowledge (clear) most current warnings or service
messages. Some warnings that cannot be
acknowledged (cleared) are: ENGINE OVERHEATED,
OIL PRESSURE LOW, REDUCED ENGINE POWER,
TRANS HOT IDLE ENGINE. These warnings must
be dealt with immediately and therefore cannot
be cleared until the problem has been corrected.
The DIC has different modes which can be accessed
by
pressing the four buttons on the DIC. These buttons
are trip information, fuel information, personalization and
select. The button functions are detailed in the
following.
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OIL LIFE RESET ENGINE COOLANT HOT
This message will appear on the display for about
10 seconds after resetting the change engine oil
message.
OIL PRESSURE LOW
If low oil pressure levels occur, this message will be
displayed on the DIC and a chime will sound. Stop the
vehicle as soon as safely possible and do not operate
it until the cause of the low oil pressure has been
corrected. Check your oil as soon as possible and have
your vehicle serviced.
CHECK OIL LEVEL
If the oil level in the vehicle is low, this message will
appear on the DIC. Check the oil level and correct it as
necessary. You may need
to let the vehicle cool or
warm up and cycle the ignition
to be sure this message
will clear. Once the problem is corrected, pressing
the select button will clear this message from the DIC
display. This message will clear itself after
10 seconds
until the next igntion cycle.
LOW COOLANT LEVEL
If the engine coolant level is low, this message will
appear on the DIC. Adding coolant will clear the
message. This message will clear itself after
10 seconds
until the next igntion cycle. If
the cooling system temperature gets hot, this message
will appear in the DIC. Stop the vehicle and
let the
engine idle in PARK
(P) to allow the coolant to reach a
safe temperature. This message will clear when the
coolant temperature drops
to a safe operating
temperature.
ENGINE OVERHEATED
If the engine cooling system reaches unsafe
temperatures for operation, this message will appear in
the DIC and you will hear a chime. Stop and turn
off
the vehicle as soon as it is safe to do so to avoid severe
damage. This message will clear when the engine
has cooled
to a safe operating temperature.
REDUCED ENGINE POWER
This message is displayed and you will hear a chime
when the cooling system temperature gets too hot
and the engine further enters the engine coolant
protection mode.
See
Engine Overheating on page 5-25 for further
information.
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BATTERY
If the battery is not charging during operation, this
message will appear
on the DIG. Driving with this
problem could drain your battery. Have the electrical
system checked as soon as possible. Pressing the
select button will acknowledge this message and clear
it
from the DIC display.
SERVlCE AIR
If there is a problem with the air bag system, this
message will be displayed on the DIC. Have a qualified
technician inspect the system for problems. Pressing
the select button will acknowledge this message
and clear
it from the DIC display.
SERVICE BRAKE SYSTE
If a problem occurs with the brake system, this message
will appear on the DIC. If this message appears, stop
as soon as possible and turn
off the vehicle. Restart the
vehicle and check for the message
on the DIC display.
If the message is still displayed, or appears again when
you begin driving, the brake system needs service.
SERVICE 4W
If a problem occurs with the all-wheel drive system? this
message will appear on the DIG.
If this message
appears, stop as
soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
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on the DIC display. If the message is still displayed, or
appears again when you begin driving, the four
wheel drive system needs service.
ONTROL
If a problem occurs with the suspension system, this
message will appear on the DIC.
If this message
appears, stop and turn
off the vehicle. Restart the
vehicle and check for the message on the
DIC display.
If the message is still displayed, or appears again
when you begin driving, the suspension system needs
service.
TURN SIGNAL ON
If a turn signal is left on for 3/4 of a mile (1.2 km), this
message will appear on the display and you will hear a
chime. Move the turn signal/multifunction lever
to the
off position. Pressing the select button will acknowledge
this message and clear
it from the DIC display.
If the liftgate is open while the ignition is in
RUN, this
message will appear on the DIC and you will hear
a chime. Turn
off the vehicle and check the liftgate.
Restart the vehicle and check for the message on the
DlC display. Pressing the select button will acknowledge
this message and clear it from the
DIC display.

When the system activates, you may hear a noise or
feel a vibration in the brake pedal. This is normal. When
the STABILITY SYS ACTIVE message is on, you
should continue
to steer in the direction you want to go.
The system is designed
to help you in bad weather
or other difficult driving situations by making the most of
whatever road conditions will permit.
SERVICE STABILITY
If you ever see the SERVICE STABILITY message, it
means there may be a problem with your
StabiIitrak@system. If you see this message
try to reset
the system (stop; turn
off the engine; then start the
engine again). If the SERVICE STABILITY message still
comes on, it means there is a problem. You should
see your dealer for service. The vehicle is safe to drive,
however, you do not have the benefit of Stabilitrak@,
so reduce your speed and drive accordingly.
STABILITY SYS DISABLED
The STABILITY SYS DISABLED message will turn on
when you press the Stabilitrak@button, or when the
stability control has been automatically disabled. To limit
wheel spin and realize the full benefits of the stability
enhancement system, you should normally leave
Stabilitrak@on. However, you should turn Stabilitrak@off
if your vehicle gets stuck in sand, mud, ice or snow and you want to “rock”
your vehicle
to attempt to free it,
or if you are driving in extreme off-road conditions
and require more wheel spin. See If
You Are Stuck: In
Sand, Mud, Ice or
Snow on page 4-41. To turn the
Stabilitrak@system back on press the Stabilitrak@button
again. There are four conditions that can cause this
message
to appear. One condition is overheating, which
could occur
if Stabilitrak@activates continuously for an
extended period of time. The message will
also be
displayed
if the brake system warning light is on. See
Brake System Warning Light
on page 3-34. The
message could be displayed
if the stability system takes
longer than usual to complete its diagnostic checks
due to driving conditions. Also,
if an engine or vehicle
related problem has been detected, and the vehicle
needs service, the message will appear.
The message will turn off as soon as the conditions that
caused the message to be displayed are no longer
present.
TRACTION ACTIVE
When the traction control system has detected that any
of the vehicle’s wheels are slipping, the traction
control system will activate and this message will appear
on the DIC. See StabiIitrakO System
on page 4-9 for
more information.
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