2000 GMC SIERRA light

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2-80 Malfunction Indicator Lamp
(Service Engine Soon 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 SERVICE ENGINE SOON 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 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
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.

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2-81
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.
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.

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2-82
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel (see
ªFuelº in the Index). 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.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 in order to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the
SERVICE ENGINE SOON 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.

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2-84 Cruise Light (If Equipped)
The CRUISE light comes
on whenever you set your
cruise control. See ªCruise
Controlº in the Index.
4WD Light (If Equipped)
The 4WD indicator will
light up when you shift a
manual transfer case into
four
-wheel drive and the
front axle engages.
Some delay between shifting and the indicator's lighting
is normal.
See ªFour
-Wheel Driveº in the Index for
more information.
Tow/Haul Light (Automatic
Transmissions Only)
This message is displayed
when the tow/haul mode has
been activated.
For more information see, ªTow/Haul Modeº in
the Index.
Fuel Gage
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 E (Empty) before you are out of
fuel, and you should get more fuel as soon as possible.

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2-85
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 F (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 E (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.

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BLEND: Airflow is delivered through the heater
floor outlets, center floor console outlets (if equipped),
the windshield defroster outlets and the side window
defroster outlets. The air flow can be divided between
HEATER and DEFROST depending upon where
the knob is placed between the settings. The air
conditioning compressor may run to dehumidify
the air to prevent window fogging.
DEFROST: This setting directs most of the air
through the windshield defroster outlets, side window
defroster outlets and some air through the heater outlets
and center floor console outlets (if equipped). If air from
the center floor console outlets is not desired or more
defroster performance is desired, turn the vents off at the
console. When in the DEFROST mode, the air
conditioning compressor may run to dehumidify the air
to prevent window fogging.
OUTSIDE AIR: Press this button to direct the
system to use outside air.
Pressing the OUTSIDE AIR button will cancel the
RECIRCULATION button.
RECIRCULATION: Press this button to limit
the amount of fresh outside air entering your vehicle.
This is helpful when you are trying to limit odors
entering your vehicle, because the air inside the vehicle
is being recirculated. Pressing RECIRCULATION will
recirculate air continuously.
RECIRCULATION is used when the fan control is OFF
to limit odors, outside air and dust from entering your
vehicle. All button lights will go off. The last setting
selected will activate when the blower is turned back on.
Pressing the RECIRCULATION button will cancel the
OUTSIDE AIR button.
In the BLEND mode, outside air is forced to reduce
window fogging. If the RECIRCULATION button is
pressed, the LED indicator will flash three times
indicating that forced outside air is activated.
The auto recirculation feature will activate when:

the air conditioning system is activated,

the OUTSIDE AIR button is on, and

the vehicle load is high due to city traffic, extended
idling or hot weather.

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The system will automatically switch to the recirculation
mode to lower the system load and improve interior
comfort. The OUTSIDE AIR and RECIRCULATION
button LEDs will not change. The system will return to
the OUTSIDE AIR function when the system load
is reduced.
A/C: Press this button to turn the air conditioning
on and off. The system will cool and dehumidify the air
inside the vehicle when the A/C light is on.
Air conditioning will be automatically disabled when
the outside temperature drops below a level at which air
conditioning is ineffective.
Air Conditioning
On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.
The RECIRCULATION button allows the air inside
your vehicle to be recirculated. This setting helps to
maximize your air conditioner's performance and your
vehicle's fuel economy. This setting also cools air the
fastest and can be used to keep unwanted odors
and/or dust from entering the vehicle.
When using the air conditioner, turn off theRECIRCULATION button after the vehicle reaches a
comfortable interior temperature. When the right knob
on the control panel is between HEATER and
DEFROST, the recirculation feature will not function to
reduce window fogging.
The A/C button, below the mode knob, allows the air
coming into your vehicle to be cooled. This setting is
useful for normal cooling on hot days. When you use
A/C with the RECIRCULATION button pushed in, turn
off recirculation as soon as the vehicle reaches a
comfortable interior temperature.
Maximum air conditioning performance is obtained by
pressing the A/C button, the RECIRCULATION button
and turning the temperature knob fully counterclockwise
to the blue area. This setting also cools air the fastest.
After the vehicle's interior reaches a comfortable
temperature, press the OUTSIDE AIR button to place
the air conditioning system in the normal mode.
Passenger Compartment Air Filter (If Equipped)
If your vehicle has air conditioning, it is equipped with a
passenger compartment air filter, which filters outside
air entering the vehicle. For information on replacing the
filter see ªPassenger Compartment Air Filterº in
the Index.

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3-9 AM-FM Stereo
Playing the Radio
VOLUME: This knob turns the system on and off
and controls the volume. To increase volume and
turn the radio on, turn the knob clockwise. Turn it
counterclockwise to decrease volume and turn the
radio off.
RECALL: Display the time with the ignition off by
pressing the recall knob. When the radio is playing,
press this knob to recall the station frequency.Finding a Station
AM
-FM: Press the lower knob to switch between AM
and FM. The display shows your selection.
TUNE: Turn the lower knob to tune in radio stations.
SEEK: Press the right arrow to tune to the next higher
station and the left arrow to tune to the next lower
station and stay there.
SCAN: Select either AM, FM1 or FM2 mode and press
both SEEK buttons to listen to a few seconds of each
radio station. SCAN will light up on the display. The
radio will automatically SCAN to the next higher
station, play that station for a few seconds, then SCAN
to the next higher station. Press VOLUME or both
SEEK buttons to stop scanning.