2004 CHEVROLET SILVERADO AIR

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 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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A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem
causing low oil pressure. Check your oil as soon as
possible. SeeOil Pressure LowunderDIC Warnings
and Messages on page 3-64andEngine Oil on
page 5-20.
{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.
Cruise Control Light
The cruise light comes on
whenever you set your
cruise control. See “Cruise
Control” underTurn
Signal/Multifunction Lever
on page 3-7.
Four-Wheel-Drive Light
The four-wheel drive
indicator will light up when
you shift a manual
transfer case into
four-wheel drive and the
front axle engages.
Some delay between shifting and the indicator’s
lighting is normal.
SeeFour-Wheel Drive on page 2-36for
more information.
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BUCKLE SEATBELT
If your vehicle is equipped with the passenger sensing
system, this message reminds you to buckle the
driver’s and/or passenger’s seatbelt. SeePassenger
Sensing System on page 1-78. The message will come
on when the ignition is in RUN and the following
conditions occur:
The driver’s seatbelt is unbuckled.
The driver’s seatbelt is unbuckled and the
passenger’s seatbelt is unbuckled with the
passenger airbag enabled.
Press the select button to acknowledge the message
and clear it from the DIC display.
BUCKLE PASSENGER
If your vehicle is equipped with the passenger sensing
system, this message reminds you to buckle the
passenger’s seatbelt. SeePassenger Sensing System
on page 1-78. This message will come on and a
chime will sound when the ignition is in RUN and the
driver’s seatbelt is buckled and the passenger’s seatbelt
is unbuckled with the passenger airbag enabled.
Press the select button to acknowledge this message
and clear it from the DIC display.
CARGO LAMP ON
If the cargo lamp is on, this message will appear on the
DIC and you will hear a chime. Turn off the vehicle
and check the liftgate. Restart the vehicle and check for
the message on the DIC display. Press the select
button to acknowledge the message and clear it from
the DIC display.
CHECK OIL LEVEL
If your vehicle is equipped with an oil level sensor, and
the oil level in the vehicle is low, this message will
appear on the DIC. Check the oil level and correct it as
necessary. You may need to let the vehicle cool or
warm up and cycle the ignition to be sure this message
will clear. Once the problem is corrected, pressing
the select button will clear this message from the DIC
display. SeeEngine Oil on page 5-20.
CHECK WASHER FLUID
If the washer uid level is low, this message will appear
on the DIC. Adding washer uid will clear the message.
Press the select button to acknowledge the message
and clear it from the DIC display. SeeWindshield
Washer Fluid on page 5-47.
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RIGHT REAR DOOR AJAR (Crew Cab)
If the passenger’s side rear door is not fully closed,
this message will appear on the display and you
will hear a chime. Stop and turn off the vehicle, check
the door for obstacles, and close the door again. Check
to see if the message still appears on the DIC. Press
the select button to acknowledge the message and clear
it from the DIC display.
SERVICE AIRBAG
If there is a problem with the air bag system, this
message will be displayed on the DIC. Have a qualied
technician inspect the system for problems. Press
the select button to acknowledge the message and clear
it from the DIC display.
SERVICE BRAKE SYSTEM
If there is a problem with the brake system, this
message will be displayed on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the brake
system needs service.
SERVICE BRAKE BOOSTER
If your vehicle has vaccum assist power brakes, this
message will be displayed on the DIC when there is a
problem with the Supplemental Brake Assist system.
If the message is displayed immediately after starting
the vehicle or the message appears while driving,
your Supplemental Brake Assist system needs service.
SeeBrake System Warning Light on page 3-43.
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{CAUTION:
Your brake system may not be working
properly if the SERVICE BRAKE BOOSTER
message is displayed.
If the brake system warning light is also
on, you should have the vehicle towed for
service. See “Brake System Warning Light” in
the Index.
If the brake system warning light isn’t on, you
still have brakes, but the supplemental brake
assist system may not operate properly. In the
event of a vacuum loss, you may not have
vacuum power assist for braking. The brake
pedal will be harder to push and it will take
longer to stop. If you continue to drive with
this message displayed it can lead to a
crash. Have the brake system serviced as
soon as possible.
SERVICE 4 WHEEL STEER
If a problem occurs with the 4-wheel steer system, this
message will appear on the DIC. If this message
appears, stop as soon as possible, and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you being driving, the four-wheel
steer system needs service.
SERVICE 4WD
If a problem occurs with the four-wheel drive system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the four wheel
drive system needs service.
SERVICE RIDE CONTROL
If a problem occurs with the suspension system, this
message will appear on the DIC. If this message
appears, stop and turn off the vehicle. Restart the
vehicle and check for the message on the DIC display.
If the message is still displayed, or appears again
when you begin driving, the air suspension system
needs service.
3-69

TIGHTEN FUEL CAP
If the vehicle’s fuel cap is not tightened properly this
message may appear along with the check engine light
on the instrument panel. SeeMalfunction Indicator
Lamp on page 3-48. Fully reinstall the fuel cap.
SeeFilling Your Tank on page 5-9. 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 and message off.
TRACTION ACTIVE
When the traction control system has detected that any
of the vehicle’s wheels are slipping, the traction
control system will activate and this message will appear
on the DIC. For more information see “Traction Assist”
in the Index.Traction Assist System (TAS) on
page 4-9.
TRANSMISSION HOT
If the transmission uid temperature becomes high, the
message center will display this message.
When the transmission enters the protection mode, you
may notice a change in the transmission shifting
patterns. When the transmission uid temperature
returns to normal, the display will turn off and the
transmission shifting patterns will return to normal.
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed on
the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by
your warranty. Do not drive your vehicle with
overheated transmission uid or while transmission
temperature warning is displayed.
3-70

The following situations can cause the transmission to
operate at higher temperatures:
Towing a trailer
Hot outside air temperatures
Hauling a large or heavy load
Low transmission uid level
High transmission uid level
Restricted air ow to the radiator and the auxiliary
transmission oil cooler.
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
on page 6-4for the proper transmission maintenance
intervals. Also seeTransmission Temperature Gage on
page 3-46for more information.
TRANS HOT IDLE ENGINE
(Allison Transmission®Only)
If the transmission uid in the vehicle gets hot, this
message will appear on the DIC, and you will hear a
chime. The chime will stop when the transmission uid
temperature is less that 265°F (129°C). Driving with
the transmission uid temperature high can cause
damage to the vehicle. Stop the vehicle and let it idle to
allow the transmission to cool. This message will
clear when the uid temperature reaches a safe level.
SeeTransmission Temperature Gage on page 3-46.
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed on
the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by
your warranty. Do not drive your vehicle with
overheated transmission uid or while transmission
temperature warning is displayed.
3-71

XM™ Radio Messages
Radio Display
MessageCondition Action Required
XL (Explicit Language
Channels)XL on the radio display,
after the channel name,
indicates content with
explicit language.These channels, or any others, can be blocked at a
customer’s request, by calling 1-800-852-XMXM (9696).
Updating Updating
encryption codeThe encryption code in the receiver is being updated, and
no action is required. This process should take no longer
than 30 seconds.
No Signal Loss of signal The system is functioning correctly, but the vehicle is in a
location that is blocking the XM signal. When you move into
an open area, the signal should return.
Loading XM Acquiring channel audio
(after 4 second delay)The audio system is acquiring and processing audio and
text data. No action is needed. This message should
disappear shortly.
CH Off Air Channel not in service This channel is not currently in service. Tune to
another channel.
CH Unavail Channel no
longer availableThis previously assigned channel is no longer assigned.
Tune to another station. If this station was one of the
presets, choose another station for that preset button.
No Info Artist Name/Feature
not availableNo artist information is available at this time on this channel.
The system is working properly.
No Info Song/Program Title
not availableNo song title information is available at this time on this
channel. The system is working properly.
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