light GMC SIERRA 2001 Workshop Manual

2-86
Air Bag Off Light
When you turn the right front passenger's air bag off,
this light will come on and stay on to remind you that
the air bag has been turned off. This light will go off
when you turn the air bag back on again. See ªAir Bag
Off Switchº in the Index for more on this, including
important safety information.CAUTION:
If the right front passenger's air bag is turned off
for a person who isn't in a risk group identified
by the national government, that person won't
have the extra protection of an air bag. In a
crash, the air bag wouldn't be able to inflate and
help protect the person sitting there. Don't turn
off the passenger's air bag unless the person
sitting there is in a risk group. See ªAir Bag Off
Switchº in the Index for more on this, including
important safety information.

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CAUTION:
If the air bag readiness light ever comes on when
you have turned off the air bag, it means that
something may be wrong with the air bag system.
The right front passenger's air bag could inflate
even though the switch is off.
If your vehicle is a regular cab pickup and this
ever happens, don't let anyone whom the
national government has identified as a member
of a passenger air bag risk group sit in the right
front passenger's position (for example, don't
secure a rear
-facing child restraint in your
vehicle) until you have your vehicle serviced.
If your vehicle is an extended cab pickup and this
ever happens, don't let anyone whom the
national government has identified as a member
of a passenger air bag risk group sit in the right
front passenger's position (for example, don't
secure a rear
-facing child restraint in the right
front passenger's seat) until you have your
vehicle serviced.
Voltmeter
United States Canada
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.

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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.
Shift Light (If Equipped)
This light is used on
some models with
manual transmissions.
The SHIFT indicator light will help you get the best fuel
economy. See ªShift Lightº or ªShift Speedsº in the
index for more information.
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, there could be a brake
problem. Have your brake system inspected right away.
United States Canada

2-89
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 ªTowing Your Vehicleº in
the Index.
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'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 stays on, or comes on when you're driving,
your vehicle needs service. 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. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly 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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Low Traction Light (If Equipped)
If you have the Traction
Assist System, this light
will come on when the
system is limiting wheel
spin. See ªTraction Assist
Systemº in the Index.
You may feel or hear the system working or notice a
lack of accelerator response, but this is normal.
The LOW TRACTION light also comes on briefly when
you turn your 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 tell you when the Traction Assist
System is active. Slippery road conditions may exist if
the LOW TRACTION light comes on, so adjust your
driving accordingly.
Traction Off Light (If Equipped)
If you have the Traction
Assist 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.
If the TRACTION OFF light stays on, or comes on
when you're driving, there may be a problem with your
Traction Assist System and your vehicle may need
service. When this light is on, the system will not limit
wheel spin. Adjust your driving accordingly.

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The TRACTION OFF light may come on for the
following reasons:

If you turn the system off by pressing the TAS on/off
button the light will come on and stay on. To turn the
system back on, press the button again; the light
should go off.

If you move the shift lever to FIRST (1), the light
will come on and stay on to indicate that the Traction
Assist System is off. This is normal operation. To
turn the system back on, move the shift lever back to
a position other than FIRST (1); the light should go
off. See ªTraction Assist Systemº in the Index.

The light will come on and stay on if the TAS automatic
engagement feature has been turned off. To turn the
system on, press the TAS off/on button; the light should
go off. To turn the automatic engagement feature back
on, see ªTraction Assist Systemº in the Index.

If the Traction Assist System is affected by an
anti
-lock brake system, Traction Assist System or
engine
-related problem, the system will turn off and
the light will come on. Have your vehicle serviced.

If the vehicle is driven over an extremely rough road,
the system will turn off and the light will come on.
The light will go off a few seconds after the rough
road conditions go away or when the vehicle comes
to a complete stop. This is normal operation.
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.

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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
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.
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.

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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.
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.

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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 or 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
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.
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 ªCheck Eng Oil Pressureº and
ªEngine Oilº in the Index.

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CAUTION:
Don't keep driving if the oil pressure is low.
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.
Cruise Light (If Equipped)
United States Canada
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.