2004 CHEVROLET COLORADO check engine light

Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, activate the system by
locking the doors with the remote keyless
entry transmitter.
2. Unlock the door with the manual door lock and
open the door. This should set off the alarm.
3. To turn the alarm off, press the unlock button on
the remote keyless entry transmitter or start
the engine.
If the alarm does not sound when it should but the lights
ash, check to see if the horn works. The horn fuse
may be blown. To replace the fuse, seeFuses
and Circuit Breakers on page 5-104.
If the alarm does not sound or the headlamps do not
ash, see your dealer for service.
Passlock®
Your vehicle is equipped with the Passlock®
theft-deterrent system.
Passlock
®is a passive theft-deterrent system. Passlock®
enables fuel if the ignition lock cylinder is turned with
a valid key. If a correct key is not used or the ignition
lock cylinder is tampered with, the fuel system is
disabled and the vehicle will not start.
During normal operation, the security light will turn off
approximately ve seconds after the key is turned
to RUN. SeeSecurity Light on page 3-28.
If the engine stalls and the security light ashes, wait
about 10 minutes until the light stops ashing before
trying to restart the engine. Remember to release
the key from START as soon as the engine starts.
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If the engine does not start after three tries, the vehicle
needs service.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the engine
off. However, your Passlock
®system is not working
properly and must be serviced by your dealer. Your
vehicle is not protected by Passlock
®at this time. You
may also want to check the fuse seeFuses and Circuit
Breakers on page 5-104. See your dealer for service.
In an emergency, call the GM Roadside Assistance
Center. SeeRoadside Assistance Program on page 7-6.
Starting and Operating
Your Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
“break-in.” But it will perform better in the long run
if you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one speed — fast or
slow — for the rst 500 miles (805 km). Do not
make full-throttle starts.
Avoid making hard stops for the rst
200 miles (322 km) or so. During this time your
new brake linings are not yet broken in. Hard
stops with new linings can mean premature
wear and earlier replacement. Follow this
breaking-in guideline every time you get new
brake linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-57for more information.
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Operation Tips

Clear away any ice, snow or leaves from the air
inlets at the base of the windshield that may
block the ow of air into your vehicle.
Use of non-GM approved hood deectors may
adversely affect the performance of the system.
Keep the path under the front seats clear of objects
to help circulate the air inside of your vehicle
more effectively.
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 briey 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.
Your vehicle may also have a DIC that works along with
the warning lights and gages. SeeDriver Information
Center (DIC) on page 3-30for more information.
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Engine Coolant Temperature Gage
This gage shows
the engine
coolant temperature.
If the gage pointer is near the top of the gage, the
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 5-28for
more information.
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.
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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:Modications made to the engine,
transmission, 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.
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 misre condition has been
detected. A misre 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 ashing and remains on steady, see “If
the Light Is On Steady” following.
If the light continues to ash, 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
ashing, follow the previous steps, and see your dealer
for service as soon as possible.
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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.
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, misring, 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 x
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.
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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.
Oil Pressure Light
{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.This light tells you if there
could be a problem with
your engine oil pressure.
The light goes on when you turn your key to ON or
START. It goes off once you start your engine. That’s a
check to be sure the light works. If it doesn’t come
on, be sure to have it xed so it will be there to warn
you if something goes wrong.
When the light comes on and stays on, it means that oil
isn’t owing through your engine properly. You could
be low on oil and you might have some other system
problem. SeeEngine Oil on page 5-13and “OIL” under
DIC Warnings and Messages on page 3-32for
more information.
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AC (Air Conditioning) OFF
This message will be displayed when the engine coolant
temperature is too high and the air conditioning in
your vehicle needs to be turned off. See andEngine
Overheating on page 5-28andClimate Control System
on page 3-12for more information. It will be displayed
along with the ENG HOT message.
ABS (Anti-Lock Brake System)
This message will be displayed on the DIC if there is a
problem with your antilock brake system. Check
your antilock brake system as soon as possible and
have your vehicle serviced by your GM dealer.
SeeBrakes on page 5-39andAnti-Lock Brake System
Warning Light on page 3-23for more information.
Pressing the reset stem to acknowledge this message
and clear it from the DIC display.
BATTERY
This message will be displayed when there is a problem
with your vehicle’s battery. SeeBattery on page 5-42
andBattery Warning Light on page 3-21for
more information.
BRAKES
This message will be displayed on the DIC if there is a
problem with your brakes. Check your brakes as
soon as possible and have your vehicle serviced by
your GM dealer. SeeBrakes on page 5-39andBrake
System Warning Light on page 3-22for more
information. Press and release the reset stem to
acknowledge the message and clear it from the
DIC display.
CHANGE OIL
This message will be displayed on your DIC when the
oil needs to be changed. Check the oil in your vehicle as
soon as possible and have your vehicle serviced by
your GM dealer. SeeEngine Oil on page 5-13and
Scheduled Maintenance on page 6-4for more
information. Press the reset stem to acknowledge the
message and clear it from the display.
DOORS
This message will be displayed on your DIC when one
of your doors is ajar. You should check all the doors
on your vehicle to make sure they are closed. The
message will clear from the display after all of the doors
are closed.
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