2004 PONTIAC GTO check engine light

Remote Keyless Entry System
Operation
The buttons on your key
allow you to lock and
unlock your doors
or unlock your trunk.
When pressing the key buttons, ensure that other keys
on the key ring are not between the main key and
the vehicle. Other keys can obscure the signal being
transmitted to the vehicle.
When a button on the key is pressed, it sends a signal
to the vehicle. The receiver of the signal is a small
rectangle on top of the dashboard, in the center. The
receiver is also used to measure sunlight. It is important
that the receiver is clean, not covered, and that there
are no metal objects close by, as this may block
the signals.LOCK:Press this button on the key to lock all the
doors, disable the engine, and set the alarm. The
vehicle’s turn signals will briefly flash.
If you prefer to have the turn signals flash accompanied
by the horn sounding, the LOCK feature can be
changed. SeeVehicle Personalization on page 2-32.
The LOCK button on the key will not work if the ignition
is turned on or if the driver’s door is open.
UNLOCK:Press this button on the key to unlock the
doors. The turn signals will flash twice, and the horn will
chirp twice, if selected through vehicle personalization.
The interior light will also turn on for a short time. If
UNLOCK is pressed once, the driver’s door will unlock.
If UNLOCK is pressed a second time, or is held
down for more than half a second, all the doors will
unlock. If you prefer to have all the doors unlock with a
single press, the unlock feature can be changed to
unlock all doors. See “Two Stage Unlock” underVehicle
Personalization on page 2-32.
If the lock system is overloaded as a result of repeated
use in a short time interval, the power supply is cut
off for about 30 seconds. The door lock system
has been designed to make the vehicle horn chirp
rapidly five times if it detects a fault in the lock system
when the LOCK button is pressed. You should check to
see that the doors have locked.
2-5

Immobilizer Operation
Your vehicle may have a passive theft-deterrent system.
The system is an electronic engine immobilizer, which
disables the car, when the key is removed from the
ignition.
The system works when you turn the key to ON. The
key uses a transponder that matches an immobilizer
control unit in your vehicle. The correct key will start
the vehicle.
Your vehicle has a special key that works with the
theft-deterrent system. There is a transponder in the key
head. If the key is ever damaged, you may not be
able to start your vehicle.
When trying to start the vehicle, if the engine does not
start and the security light comes on, the key may
have a damaged transponder. Turn the ignition off and
try again.If the engine still does not start, and the key appears to
be undamaged, try another ignition key. At this time,
you may also want to check the fuse. SeeFuses
and Circuit Breakers on page 5-87for more information
on fuses. If the engine still does not start with the
other key, your vehicle needs service. If your vehicle
does start, the first key may be faulty. See your dealer
who can service the theft-deterrent system to have
a new key made.
If you are ever driving and the security light comes on
and stays on, you will be able to restart your engine
if you turn it off. The theft-deterrent system, however, is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by the
theft-deterrent system at this time.
In an emergency, contact Roadside Assistance. See
Roadside Assistance Program on page 7-5.
2-13

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.
3-23

Charging System Light
The charging system light
will come on when you
turn on the ignition,
until the engine is started,
as a check to show
you it is working.
When the engine is running, the light should go out.
If the light illuminates and the Check Alternator message
on the trip computer stays on, or comes on while you
are driving 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.
The Check Alternator message will remain until the
MODE button on the trip computer is pressed, but the
symbol will remain until the problem is fixed.
Brake System Warning Light
To check that the light is
working, the symbol is
displayed when the ignition
is first turned ON and
the park brake applied.
If the symbol illuminates and the Brake message
appears on the trip computer display while driving and
the park brake is released, a fault with the brakes is
indicated. You should immediately stop the car on the
side of the road as carefully as possible. Do not proceed
until satisfied that braking is possible or that the
cause of the problem has been fixed.
A warning will chime if you attempt to drive off without
releasing the park brake.
The Brake message will remain until the MODE button
on the trip computer is pressed, but the symbol will
remain until the problem is fixed.
3-27

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.
3-29

Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-5. 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.
3-31

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

Trip Computer Warning Messages
Cruise Control
The CRUISE light along
with the Cruise Enabled
message on the trip
computer display will come
on whenever you set
your cruise control.
SeeTurn Signal/Multifunction Lever on page 3-5.
Engine Coolant Temperature Warning:If the Engine
Temp Hot message in the trip computer display
comes on while driving, it indicates that the engine
coolant temperature is dangerously hot. You should stop
the vehicle as soon as it is safe to do so. The Engine
Temp Hot message is displayed until the MODE button
on the trip computer switch is pressed. The message
then reverts to the original trip computer display
with a small over temperature symbol on the left. The
symbol will remain until the problem is fixed. SeeEngine
Overheating on page 5-28.
Low Coolant Warning:If the Low Coolant message in
the trip computer comes on while driving, it indicates
that the engine coolant level is dangerously low.You should check the level as soon as possible, see
Engine Coolant on page 5-25. The Low Coolant
message is displayed until the MODE button on the trip
computer switch is pressed. The message then
reverts to the original trip computer display with a small
low coolant symbol on the left. The symbol will remain
until the problem is fixed.
Low Traction:If the Low Traction message appears in
the trip computer display while driving, it indicates
that the traction control system has sensed that your
vehicle requires help with road grip and that the system
is actively working to stop any wheel spin. The Low
Traction message is displayed for about one second.
The message then reverts to the original trip computer
display with a small low traction symbol on the left.
The symbol will remain as long as the low traction
situation exits. SeeTraction Control System (TCS)
on page 4-8.
Traction Off:If the Traction Ctrl Off message in the trip
computer display comes on while driving, without the
traction control being turned off by the driver, it indicates
the traction control system is not working and you
should see your vehicle dealer. The Traction Ctrl Off
message is displayed for two seconds. The message
then reverts to the original trip computer display
with a small TRAC OFF symbol on the right. The symbol
will remain until the problem is fixed. SeeTraction
Control System (TCS) on page 4-8.
3-41