2004 CHEVROLET SILVERADO check engine light

Supplemental Brake Assist System
If your vehicle has vacuum assist power brakes, it is also
equipped with a supplemental brake assist system
that supplies additional vacuum to the vacuum brake
booster if engine vacuum is reduced. Under certain
conditions, the supplemental brake assist system may
run briey after starting your vehicle or when you
apply and release the brake pedal and it may continue
to run even after you have removed your foot from
the brake pedal. When the supplemental brake assist
system is operating, you may hear a motor running
or feel a slight vibration in the steering wheel or brake
pedal. This indicates that the supplemental brake
assist system is working to supply additional vacuum for
your vacuum assist power brakes. This is a normal
operation of your brake system and does not require that
the brake system be serviced.
Each time you start your vehicle and accelerate, the
supplemental brake assist system will perform a
self-diagnostic check of the system and you may hear
or feel the supplemental brake assist motor run
briey. While you are driving your vehicle, the
supplemental brake assist system monitors itself to
ensure that it is operating properly. If there is a problem
with the supplemental brake assist system, the
SERVICE BRAKE BOOSTER message will be displayed
on the Driver Information Center. SeeDIC Warnings
and Messages on page 3-64.If your supplemental brake assist system runs every
time you apply and release the brake pedal or you notice
that the brake pedal has suddenly become much
harder to push and the vehicle takes longer to stop, you
should have your vehicle serviced as soon as possible.
Traction Assist System (TAS)
Your vehicle may have a Traction Assist System (TAS)
that limits wheel spin. This is especially useful in
slippery road conditions. The system operates only if it
senses that one or both of the rear wheels are
spinning or beginning to lose traction. When this
happens, the system reduces engine power to limit
wheel spin.
The traction control system is enabled every time your
vehicle is started. The system will activate if it senses
that any of the wheels are spinning or beginning to
lose traction.
You may hear or feel the system working or notice a
lack of accelerator response, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you
may notice a reduction in acceleration. This is normal
and doesn’t mean there’s a problem with your vehicle.
Examples of these conditions include a hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
4-9

Put on extra clothing or wrap a blanket around you.
If you have no blankets or extra clothing, make
body insulators from newspapers, burlap bags, rags,
oor mats — anything you can wrap around
yourself or tuck under your clothing to keep warm.
You can run the engine to keep warm, but be careful.
{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You can not see it
or smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking your exhaust pipe. And check around
again from time to time to be sure snow does
not collect there.
Open a window just a little on the side of the
vehicle that is away from the wind. This will
help keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery charged. You will need a
well-charged battery to restart the vehicle, and possibly
for signaling later on with your headlamps. Let the
heater run for a while.
4-49

Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airow around it. This may cause wind
noise and affect windshield washer performance. Check
with your dealer before adding equipment to the
outside of your vehicle.
Fuel
If your vehicle has a diesel engine, see “Diesel
Fuel Requirements and Fuel System” in the Diesel
Engine Supplement.
For vehicles with gasoline engines, please read this.
Gasoline Octane
For all except the Silverado SS model, use regular
unleaded gasoline with a posted octane of 87 or higher.
If the octane is less than 87, you may get a heavy
knocking noise when you drive. If this occurs, use a
gasoline rated at 87 octane or higher as soon as
possible. Otherwise, you might damage your engine.
A little pinging noise when you accelerate or drive uphill
is considered normal. This does not indicate a problem
exists or that a higher-octane fuel is necessary.
If you are using 87 octane or higher-octane fuel and
hear heavy knocking, your engine needs service.
If you have the Silverado SS model, use premium
unleaded gasoline with a posted octane of 91 or higher
for best performance. You may also use middle
grade or regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may be slightly
reduced. If the octane is less than 87, you may get a
heavy knocking noise when you drive. If this occurs, use
gasoline rated at 87 octane or higher as soon as
possible. Otherwise, you might damage your engine.
5-5

Engine Oil
If your vehicle has a diesel engine, see “Engine Oil” in
the Diesel Engine Supplement.
If the CHECK OIL LEVEL light appears on the
instrument cluster (except vehicles equipped with the
4.3L engine), it means you need to check your engine oil
level right away.
For more information, seeDriver Information
Center (DIC) on page 3-53.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It is a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-14for
the location of the engine oil dipstick.
Turn off the engine and give the oil several minutes to
drain back into the oil pan. If you don’t, the oil
dipstick might not show the actual level.Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
All Other Engines
8.1L Engine
5-20

When to Check and What to Use
The clutch master cylinder
reservoir is located in the
rear of the engine
compartment on the
driver’s side of the vehicle.
SeeEngine Compartment
Overview on page 5-14
for more information
on location.
Refer to the Maintenance Schedule to determine how
often you should check the uid level in your clutch
master cylinder reservoir and for the proper uid. See
Owner Checks and Services on page 6-9and
Recommended Fluids and Lubricants on page 6-13.
How to Check and Add Fluid
The proper uid should be added if the level does not
reach the bottom of the diaphragm when it’s in place in
the reservoir. See the instructions on the reservoir cap.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs rst, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, seeEngine Overheating on
page 5-38.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as
they should.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
5-35

On V6 engines the remote negative (−) terminal is
located on a tab attached to the engine accessory
drive bracket where it is marked “GND.”
SeeEngine Compartment Overview on page 5-14
for more information on location.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
Be sure the battery has enough water. You do
not need to add water to the ACDelco
®battery
installed in your new vehicle. But if a battery
has ller caps, be sure the right amount of
uid is there. If it is low, add water to take care
of that rst. If you do not, explosive gas could
be present.
Battery uid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, ush the place
with water and get medical help immediately.
{CAUTION:
Fans or other moving engine parts can injure
you badly. Keep your hands away from moving
parts once the engine is running.
6. Check that the jumper cables don’t have loose or
missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) will go to
positive (+) or a remote positive terminal (+) if the
vehicle has one. Negative (−) will go to a heavy,
unpainted metal engine part or a remote
negative (−) terminal if the vehicle has one.
Don’t connect positive (+) to negative (−) or you’ll
get a short that would damage the battery and
maybe other parts too. And don’t connect the
negative (−) cable to the negative (−) terminal on
the dead battery because this can cause sparks.
On vehicles equipped with dual batteries, make all
battery connections to the remote positive (+)
and remote negative (−) terminals.
5-55

C
California Fuel.................................................. 5-6
Canada – Customer Assistance.......................... 7-5
Canadian Owners................................................ ii
Canadian Roadside Assistance........................... 7-7
Capacities and Specications..........................5-132
Car Washes for QUADRASTEER™
Equipped Vehicles.......................................4-17
Carbon Monoxide...................2-15, 2-53, 4-46, 4-70
Care of
Safety Belts..............................................5-117
Your Cassette Tape Player..........................3-129
Your CD and DVD Player...........................3-130
Your CDs and DVDs..................................3-130
Cargo Lamp...................................................3-17
CARGO LAMP ON.........................................3-65
Cassette Tape Messages.................................3-97
CD Adapter Kits.............................................3-97
CD Messages...............................3-86, 3-99, 3-113
Center Console Storage Area...........................2-68
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp...............................................5-68
Center Instrument Panel Fuse Block................5-126
Center Passenger Position, Safety Belts.............1-24
Chains, Tires..................................................5-91
CHANGE ENGINE OIL....................................3-66
Check Engine Light.........................................3-48
CHECK OIL LEVEL.........................................3-65CHECK WASHER FLUID.................................3-65
Checking Brake Fluid......................................5-50
Checking Coolant............................................5-36
Checking Engine Oil........................................5-20
Checking Things Under the Hood......................5-12
Chemical Paint Spotting.................................5-120
Child Restraints
Child Restraint Systems...............................1-38
Infants and Young Children...........................1-34
Lower Anchorages and Top Tethers for
Children (LATCH System)..........................1-47
Older Children.............................................1-32
Securing a Child Restraint Designed for the
LATCH System................................1-48, 1-49
Securing a Child Restraint in a Center Rear
Seat Position...........................................1-56
Securing a Child Restraint in a Rear Outside
Seat Position...........................................1-53
Securing a Child Restraint in the Center Front
Seat Position...........................................1-58
Securing a Child Restraint in the Right Front
Seat Position (Crew Cab)..........................1-58
Securing a Child Restraint in the Right
Front Seat Position (Regular and
Extended Cab).........................................1-61
Top Strap...................................................1-42
Top Strap Anchor Location............................1-43
Where to Put the Restraint...........................1-41
3

E
Easy Exit Seat...............................................2-72
Electrical System
Add-On Equipment.....................................5-123
Fuses and Circuit Breakers.........................5-123
Power Windows and Other Power Options.......5-123
Windshield Wiper Fuses.............................5-123
Electronic Transfer Case..................................2-44
Emissions Inspection and Maintenance
Programs...................................................3-50
Engine
Air Cleaner/Filter.........................................5-25
Battery.......................................................5-52
Check and Service Engine Soon Light............3-48
Coolant......................................................5-35
Coolant Heater............................................2-26
Coolant Temperature Gage...........................3-46
Drive Belt Routing.......................................6-18
Engine Compartment Overview......................5-14
Exhaust.....................................................2-53
Fan Noise..................................................5-46
Oil .............................................................5-20
Overheating................................................5-38
Starting......................................................2-24
ENGINE COOLANT HOT.................................3-66
Engine Hour Meter Display...............................3-35
Engine Oil Additives........................................5-23
ENGINE OVERHEATED..................................3-66Entry Lighting.................................................3-18
Environmental Concerns..................................4-25
Event Data Recorders (EDR)............................. 7-9
Exit Lighting...................................................3-18
Express Down Windows..................................2-18
Extended Cab........................................1-56, 2-14
Extended Cab and Crew Cab...........................1-53
Extender, Safety Belt.......................................1-31
Exterior Lamps...............................................3-13
F
Fifth Wheel and Gooseneck Trailering................4-89
Filter
Engine Air Cleaner......................................5-25
Finding a Program Type (PTY) Station
(RDS and XM™).......................3-79, 3-90, 3-104
Finding a Station..................3-74, 3-77, 3-88, 3-102
Finish Care..................................................5-118
Finish Damage.............................................5-120
Five-Speed (VORTEC™ 4300 V6 and
4800 V8 Engines)........................................2-32
Five-Speed (VORTEC™ 6000 V8 Engine)...........2-31
Fixed Mast Antenna.......................................3-130
Flash-to-Pass................................................... 3-9
Flat Tire........................................................5-92
Flat Tire, Changing.........................................5-93
6