2004 CHEVROLET EXPRESS check engine light

Theft-Deterrent Systems
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make it
impossible to steal.
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, fuel is disabled.
During normal operation, the SECURITY light will go off
approximately ve seconds after the key is turned to
RUN. SeeSecurity Light on page 3-36.
If the engine stalls and the SECURITY light ashes,
wait until the light stops ashing before trying to restart
the engine. Remember to release the key from
START as soon as the engine starts.
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 5-92. See your dealer
for service.
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 4-34for more information.
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Cruise Control Light......................................3-36
Reduced Engine Power Light.........................3-37
Highbeam On Light.......................................3-37
Daytime Running Lamps (DRL)
Indicator Light...........................................3-37
Tow/Haul Mode Light....................................3-38
Check Gages Warning Light...........................3-38
Fuel Gage...................................................3-38
Audio System(s).............................................3-39
Setting the Time for Radios without Radio
Data Systems (RDS)..................................3-40
Setting the Time for Radios with Radio
Data Systems (RDS)..................................3-40AM-FM Radio...............................................3-40
Radio with CD..............................................3-43
Radio with Cassette and CD..........................3-47
Radio with Six-Disc CD.................................3-60
Theft-Deterrent Feature (Non-RDS Radios).......3-71
Theft-Deterrent Feature (RDS Radios).............3-71
Radio Reception...........................................3-72
Care of Your Cassette Tape Player.................3-72
Care of Your CDs.........................................3-74
Care of Your CD Player................................3-74
Fixed Mast Antenna......................................3-74
Chime Level Adjustment................................3-74
Section 3 Instrument Panel
3-2

To change the current mode, select one of the following:
D(Vent):Use this mode to direct air to the upper
outlets, with a little air directed to the oor outlets.
2(Floor):Use this mode to direct most of the air to
the oor outlets.
9(Fan):Turn the left knob clockwise or
counterclockwise to HIGH, MED (Medium) or LOW to
increase or decrease the fan speed in the rear-seating
area. Turn the knob to OFF to turn off the fan.
Temperature Control:To increase or decrease the
temperature for the rear of the vehicle, turn the
right knob located on the climate-control panel.
The air-conditioning system on the main climate-control
panel must be turned on to direct cooled air to the rear of
the vehicle. If it is not on, then the temperature in the rear
of the vehicle will remain at cabin temperature.
Be sure to keep the area under the front seats clear of
any objects so that the air inside of your vehicle can
circulate effectively.
For information on how to use the main climate-control
system, seeClimate Control System on page 3-18.
For information on ventilation, seeOutlet Adjustment on
page 3-20.
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’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.
3-22

Charging System Light
This light should come on
briey when you turn on
the ignition, before starting
the engine, as a check
to show you it is working.
After the engine starts, the light should go out. If it stays
on or comes on while you are driving, you may have
a problem with your charging system. It could indicate a
problem with the generator drive belt, or some other
charging system problem. Have it checked right away.
Driving while this light is on could drain your battery.
If you must drive a short distance with this light
on, it helps to turn off all your accessories, such as the
radio and air conditioner.
Voltmeter Gage
When your engine is not
running, but the ignition is
on (in the RUN position),
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.
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.
3-28

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 awhile, 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.
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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 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.
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 5-8. The
diagnostic system can determine if the fuel cap hasbeen 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.
3-33

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.
Oil Pressure Gage
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.United States
Canada
3-34

A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem causing
low oil pressure. Check your oil as soon as possible.
{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.
Change Engine Oil Light
This light is displayed
when your vehicle needs
to be serviced.
If your vehicle has a V8 engine and this light is ashing,
it indicates that the oil level is low.
When this light is on steady, your vehicle needs to be
serviced. SeeScheduled Maintenance on page 6-4
for more information.
Once the engine oil has been changed, the change
engine oil light must be reset. Until it is reset, the light
will stay on for a while each time the engine is
started. For more information on resetting the system,
see “How to Reset the Engine Oil Life System”
underEngine Oil Life System on page 5-16.
3-35