2004 CHEVROLET CLASSIC engine

Warning Lights, Gages and
Indicators
This part describes the warning lights and gages that may
be on your vehicle. The pictures will help you locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause
an expensive repair or replacement. Paying attention to
your warning lights and gages could also save you
or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions. As you will
see in the details on the next few pages, some
warning lights come on briefly when you start the
engine just to let you know they are working. If you are
familiar with this section, you should not be alarmed
when this happens.Gages can indicate when there may be or is a problem
with one of your vehicle’s functions. Often gages
and warning lights work together to let you know when
there is a problem with your vehicle.
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual’s advice.
Waiting to do repairs can be costly — and even
dangerous. So please get to know your warning lights
and gages. They are a big help.
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Tachometer
The tachometer shows your engine speed in revolutions
per minute (rpm).
Notice:If you operate the engine with the
tachometer in the shaded warning area, your vehicle
could be damaged, and the damages would not
be covered by your warranty. Do not operate
the engine with the tachometer in the shaded
warning area.
Safety Belt Reminder Light
When the key is turned to ON or START, a chime will
come on for several seconds to remind people to fasten
their safety belts, unless the driver’s safety belt is
already buckled.
The safety belt light will
also come on and stay on
for several seconds,
then it will flash for several
more.
If the driver’s belt is already buckled, neither the chime
nor the light will come on.
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Charging System Light
The charging system light
will come on when you
turn on the ignition, but the
engine is not running, as
a check to show you it
is working.
When the engine is running, the light should go out.
If it stays on, or comes on while you are driving and you
hear a chime, you may have a problem with the
electrical charging system. It could indicate that you
have a loose generator drive belt or another electrical
problem. Have it checked right away. Driving while
this light is on could drain your battery.
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.
Brake System Warning Light
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 is a brake problem.
Have your brake system inspected right away.
This light should come on
briefly when you turn the
ignition key to ON. If it
doesn’t come on
then, have it fixed so it will
be ready to warn you if
there’s a problem.
When the ignition is on, the brake system warning light
will also come on when you set your parking brake.
The light will stay on if your parking brake doesn’t
release fully. If it stays on after your parking brake is
fully released, it means you have a brake problem.
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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. SeeTowing
Your Vehicle on page 4-29.
{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 have pulled off the road and
stopped carefully, have the vehicle towed for
service.
Anti-Lock Brake System Warning
Light
If your vehicle has the
anti-lock brake system, the
light will come on when
your engine is started and
may stay on for several
seconds. That’s normal.
If the light stays on, turn the ignition to OFF. Or, if the light
comes on and the chime sounds when you’re driving,
stop as soon as possible and turn the ignition off. Then
start the engine again to reset the system. If the light still
stays on, or comes on again while 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
Brake System Warning Light on page 3-27earlier in this
section.
The anti-lock brake system warning light will come on
briefly when you turn the ignition key to ON. This is
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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Engine Coolant Temperature Gage
This gage shows the
engine coolant
temperature.
If the gage pointer moves into the red area, the light
comes on and you hear a chime, your engine is too hot!
It means that your engine coolant has overheated.
If you have been operating your vehicle under normal
driving conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible.
SeeEngine Overheating on page 5-22.
Low Coolant Warning Light
This light comes on
briefly when you turn
your ignition ON.
If this light comes on and stays on, the coolant level in
your vehicle is low. SeeEngine Coolant on page 5-19.
If the light is on along with an overheat warning,
you may have a serious overheating problem, see
Engine Coolant Temperature Gage on page 3-29.
Notice:If you operate the engine without coolant
or fail to maintain the cooling system properly,
you could damage the engine. The repairs would not
be covered by your warranty. Always follow the
maintenance schedule in this manual for
maintaining your cooling system. SeeCooling
System on page 5-25for more information.
SeeEngine Overheating on page 5-22for information
on what to do. Your vehicle should be serviced as soon
as possible.
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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:Modications made to the engine,
transaxle, 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.
Modications 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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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 does not 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. Diagnosis and service may be
required.
•Light On Steady— An emission control system
malfunction has been detected on your vehicle.
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 see your dealer
for service as soon as possible.
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. SeeFilling 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.
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Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-4. 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,
your dealer can 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 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, your GM dealer can prepare the
vehicle for inspection.
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