2002 GMC YUKON DENALI ignition

2-72 Malfunction Indicator Lamp (Service
Engine Soon Light in the United States or
Check Engine Light in Canada)
United States Canada
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
SERVICE ENGINE SOON or 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 the SERVICE ENGINE SOON or
CHECK ENGINE 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.

2-73
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.

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
ªIf the Light Is On Steadyº 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 ªIf the Light
Is On Steadyº 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 ªFilling Your Tankº in the Index. 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.

2-76 Cruise Light
United States Canada
The CRUISE light comes on whenever you set your
cruise control. See ªCruise Controlº in the Index.
Tow/Haul Light
This light is displayed
when the tow/haul mode
has been activated.
For more information, see ªTow/Haul Modeº in
the Index.
Fuel Gage
United States Canada
The fuel gage, when the ignition is on, tells you about
how much fuel you have left in your tank.
The gage will first indicate empty before you are out of
fuel, and you should get more fuel as soon as possible.

2-77
Here are some situations you may experience with
your fuel gage. None of these indicate a problem with
the fuel gage.

At the gas station, the fuel pump shuts off before the
gage reads full.

It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may have
indicated the tank was half full, but it actually took a
little more or less than half the tank's capacity to fill
the tank.

The gage goes back to empty when you turn off
the ignition.
Message Center
The message center is located on the left side of the
instrument panel cluster. It gives you important safety
and maintenance facts. When you turn the ignition on,
the entire center lights up for just a few seconds. As
needed, the message center will display one of the
following messages. The message center is capable of
alternating among different messages if needed.
Battery
If this message is displayed
when the engine is running,
you may have a problem
with your charging system.
The battery display will also stay on while the key is in
RUN until the engine is started.
If the message stays on after starting the engine it could
indicate a problem with the generator drive belt, or some
other charging system problem. Have it checked right
away. Driving with this message displayed could drain
your battery.
If you must drive a short distance with this message
displayed, it helps to turn off all your accessories, such
as the radio and the air conditioner.

2-81 Check Eng Oil Pressure
This message is displayed
when the engine oil pressure
is low.
See ªOil Pressure Gageº in the Index for
more information.
Check Eng Oil Level
This message is displayed
when the engine oil level
is low.
Once oil is added, it may need time to drain and settle in
the engine before this message will turn off. It is best to
let the engine cool down (if it is hot) or warm up (if it is
cold) and cycle the ignition to be sure this message turns
off. Refer to the dipstick for the correct level.
See ªEngine Oilº in the Index on how to check the oil
level and for what type of oil to add.

2-82 Change Engine Oil
This message is displayed
when the engine oil needs
to be changed. The message
is only displayed for
15 seconds at the start of
each ignition cycle.
When you change the engine oil, be sure to reset the
Engine Oil Life Monitor. See ªEngine Oil, When to
Changeº in the Index.
Security
This message is displayed
when the content
theft
-deterrent system
has been activated and
also monitors the
Passlock

system.
If the security message is displayed 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 GM dealer.
Low Washer Fluid
This message is displayed
when the vehicle is low on
windshield washer fluid.
The message is only
displayed for 15 seconds
each ignition cycle.
For more information, see ªWindshield Washer Fluidº in
the Index.
Service Ride Control
This message is
displayed when a possible
problem exists with the
Autoride system.
For more information, see ªAutorideº in the Index.

2-83 Cargo Door Ajar
This message is displayed
when the rear liftglass or
liftgate is ajar when the
ignition is in RUN.
Low Fuel
This message is displayed
when your vehicle is low
on fuel.
Refer to the fuel gage for a better indication of the
amount of fuel remaining in the fuel tank.
Secondary Information Center (SIC)
This section explains the features of your SIC.
The SIC provides instant information about fuel,
mileage and vehicle history in addition to allowing you
to personalize certain features of your vehicle. If you
would like to skip to the section on personalizing your
vehicle, see the section under MENU.

2-84 Fuel

Each press of the FUEL button will change the
display between the fuel remaining range, average
fuel economy, instantaneous fuel economy and a
blank display.

The average fuel economy can be reset using the
RESET button.
Trip
Each press of the TRIP button will change the
display between personal trip computer, business trip
computer, timer, vehicle history, annual mileage and a
blank display.
Personal Trip Computer and Business
Trip Computer

Each press of the arrow button will change the
display between turn on/off, trip odometer, fuel used,
average fuel economy and average speed.

The ON/OFF button will turn the trip computer on
and off. The information on the trip computer only
gets updated when it is turned on. The personal and
business computers are independent, i.e. turning one
of them on does not turn the other off.
All information associated with the trip computer
will be reset when the RESET button is pressed.

If the RESET button is pressed and held for more
than two seconds, all of the trip computer settings
will reset starting from the last ignition cycle
(turning the ignition from OFF to RUN). This
feature is for someone who has forgotten to reset the
trip computer when pulling out of the driveway and
does not realize it until after driving for awhile.
Timer

Each press of the ON/OFF button will turn the timer
on or off.

The RESET button will reset the timer to 00:00:00.

If turned on, the timer will accumulate whenever
the SIC is powered (the engine does not have to
be running).

The timer will rollover after 99:59:59.