2004 PONTIAC GTO service

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’re 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’s 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’re a big help.
Your vehicle also has a trip computer that works along
with the warning lights and gages. The trip computer
display provides visual information. SeeTrip Computer
on page 3-36. The warning message are displayed
through the trip computer or as an illuminated symbol or
sometimes both ways.
If a Service Error Contact Dealer message appears on
the trip computer display while driving, a fault in the
instrument panel is indicated. Contact your dealer
as soon as possible. This message will remain until the
MODE button on the trip computer is pressed.
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Air Bag Readiness Light
There is an air bag
readiness light on the
instrument panel which
shows the air bag symbol.
This light along with a Airbag Fault message in the trip
computer display will come on when you start your
vehicle, and it will flash for a few seconds. Then the light
should go out. This means the system is ready.
The system checks the air bag’s electrical system for
malfunctions. The light tells you if there is an electrical
problem. The system check includes the air bag
sensors, the air bag modules, the wiring and the
diagnostic module. For more information on the air bag
system, see Supplemental Restraint System (SRS).If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air
bag system may not work properly. Have your vehicle
serviced right away. The light comes on after an
accident where the air bags were activated.
{CAUTION:
If the air bag readiness light stays on after you
start your vehicle, it means the air bag system
may not be working properly. The air bags in
your vehicle may not inate in a crash, or they
could even inate without a crash. To help
avoid injury to yourself or others, have your
vehicle serviced right away if the air bag
readiness light stays on after you start your
vehicle.
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Anti-Lock Brake System
Warning Light
To ensure that the warning
light is working, the symbol
is displayed for a short
time when the ignition is
turned to ON.
If the light doesn’t come on then, have it fixed so it will
be ready to warn you if there is a problem.
If there is a malfunction of the anti-lock brake system,
the symbol will illuminate and ABS Fault will appear
on the trip computer display. See your dealer for service.
The car’s brake system will still operate conventionally,
only the anti-lock operation is impaired.
The ABS Fault message will remain until the MODE
button on the trip computer is pressed, but the symbol
will remain until the problem is fixed.
Engine Coolant Temperature Gage
The temperature gage
shows the engine coolant
temperature when the
ignition is on.
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.
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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,
transmission, exhaust, intake or fuel system of your
vehicle or replacement tires that do not match
your vehicle’s original tires 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.
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.
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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.
3-30

Oil Pressure Light
If you have a low engine
oil pressure problem, a
Check Oil message in the
trip computer display
along with this symbol will
stay on after you start
your engine, or come on
when you are driving.
This indicates that your engine is not receiving enough
oil. The engine could be low on oil, or could have
some other oil problem. Have it fixed immediately.
When the ignition is on but the engine is not running,
the light will come on as a test to show you it is working,
but the light will go out when the engine is running. If
it doesn’t come on with the ignition on, you may have a
problem with the bulb. Have it fixed right away.{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
3-32

Change Engine Oil Light
If the Service Engine Oil
message in the trip
computer is displayed
along with this symbol after
you start the engine, it
means that service
is required for your vehicle.
SeeScheduled Maintenance on page 6-4andEngine
Oil on page 5-13for more information.
Security Light
This light flashes when the
vehicle security system is
activated.
Fog Lamp Light
This light will come on
when the fog lamps are
in use.
The light will go out when the fog lamps are turned off.
SeeExterior Lamps on page 3-12for more information.
Highbeam On Light
This light will illuminate
when the headlamp high
beams are in use.
SeeTurn Signal/Multifunction Lever on page 3-5.
3-33

Daytime Running Lamps
Indicator Light
This light will illuminate
when the Daytime Running
Lamps (DRL) are
activated. SeeExterior
Lamps on page 3-12.
Service Vehicle Soon Light
The Service Vehicle Soon
message along with this
symbol will come on and a
chime will sound if it
detects a problem on the
vehicle.
Such problems could be the Daytime Running
Lamps (DRL) or an automatic headlamp system
malfunction.
If this happens, see your dealer as soon as possible.
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