2003 GMC SIERRA check engine light

Remember: Anti-lock doesn’t change the time you need
to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to the
vehicle in front of you, you won’t have time to apply
your brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Don’t pump the brakes. Just hold the brake pedal down
rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise, but
this is normal.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
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 continueto 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 to
10 mph, 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 3-51.
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.
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2003 - Sierra Denali

Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to
move slightly slower at night.
When you want to leave the freeway, move to the
proper lane well in advance. If you miss your exit, do
not, under any circumstances, stop and back up. Drive
on to the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed is usually posted.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are
going slower than you actually are.
Before Leaving on a Long Trip
Make sure you’re ready. Try to be well rested. If you
must start when you’re not fresh—such as after a day’s
work—don’t plan to make too many miles thatrst
part of the journey. Wear comfortable clothing and shoes
you can easily drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it’s ready to go. If it needs
service, have it done before starting out. Of course,you’llnd experienced and able service experts in GM
dealerships all across North America. They’ll be
ready and willing to help if you need it.
Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir full? Are
all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you checked
all levels?
Lamps:Are they all working? Are the lenses clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough for
long-distance driving? Are the tires all inated to the
recommended pressure?
Weather Forecasts:What’s the weather outlook
along your route? Should you delay your trip a
short time to avoid a major storm system?
Maps:Do you have up-to-date maps?
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2003 - Sierra Denali

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’t 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
doesn’t collect there.
Open a window just a little on the side of the
vehicle that’s 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.
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2003 - Sierra Denali

A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Cleaner/Filter Restriction Indicator
D. Engine Oil Dipstick
E. Engine Oil Fill Cap
F. Automatic Transmission Dipstick
G. Fan
H. Remote Negative (−) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir
K. Brake Fluid Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
Engine Oil
If the CHECK OIL LEVEL light appears on the
instrument cluster, it means you need to check your
engine oil level right away. For more information,
see“CHECK OIL LEVEL”underDIC Warnings and
Messages on page 3-51.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It’s 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 has a yellow looped handle and
is located on the passenger’s side of the vehicle.
SeeEngine Compartment Overview on page 5-12for
more information on location.
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.
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2003 - Sierra Denali

Part B: Owner Checks and Services
Listed in this part are owner checks and services
which should be performed at the intervals specied to
help ensure the safety, dependability and emission
control performance of your vehicle.
Be sure any necessary repairs are completed at once.
Whenever anyuids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
in Part D.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuelfill.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-13for further
details.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL®
coolant mixture if necessary. SeeEngine Coolant
on page 5-23for further details.
Windshield Washer Fluid Level Check
Check the windshield washeruid level in the windshield
washer tank and add the properuid if necessary.
SeeWindshield Washer Fluid on page 5-35for further
details.
At Least Once a Month
Tire Inflation Check
Make sure tires are inated to the correct pressures.
Don’t forget to check your spare tire. SeeTires on
page 5-56for further details.
Cassette Tape Player Service
Clean cassette tape player. Cleaning should be done
every 50 hours of tape play. SeeAudio System(s)
on page 3-56for further details.
At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors and anchorages
are working properly. Look for any other loose or
damaged safety belt system parts. If you see anything
that might keep a safety belt system from doing its
job, have it repaired. Have any torn or frayed safety belts
replaced.
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2003 - Sierra Denali

Care of (cont.)
Your CD Player...........................................3-78
Your CDs ...................................................3-78
Cargo Lamp...................................................3-14
CARGO LAMP ON .........................................3-54
Cassette Tape Messages.................................3-67
Cassette Tape Player Service...........................6-10
CD Adapter Kits.............................................3-68
CD Changer...................................................3-73
CD Functions.................................................3-74
Center Console Storage Area...........................2-39
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.........................................5-52
Center Instrument Panel Fuse Block..................5-94
Center Passenger Position, Safety Belts.............1-21
Chains, Tires..................................................5-64
CHANGE ENGINE OIL ....................................3-52
Check
Engine Light...............................................3-37
Check Engine Light.........................................3-37
CHECK OIL LEVEL .........................................3-54
CHECK WASHER FLUID .................................3-54
Checking Brake Fluid......................................5-37
Checking Coolant............................................5-24
Checking Engine Oil........................................5-13
Checking Things Under the Hood
......................5-10
Checking Your Restraint Systems
......................1-71
Chemical Paint Spotting
...................................5-88
Child Restraints
Child Restraint Systems
...............................1-35Child Restraints (cont.)
Infants and Young Children...........................1-31
Lower Anchorages and Top Tethers for
Children (LATCH System)..........................1-42
Older Children.............................................1-29
Securing a Child Restraint Designed for the
LATCH System........................................1-45
Securing a Child Restraint in a Center Rear
Seat Position...........................................1-47
Securing a Child Restraint in a Rear Outside
Seat Position...........................................1-45
Securing a Child Restraint in the Right Front
Seat Position...........................................1-49
Top Strap...................................................1-39
Top Strap Anchor Location............................1-40
Where to Put the Restraint...........................1-38
Cigarette Lighter.............................................3-17
Cleaning
Inside of Your Vehicle..................................5-83
Outside of Your Vehicle................................5-85
Underbody Maintenance...............................5-87
Weatherstrips..............................................5-85
Cleaning Aluminum or Chrome-Plated Wheels.....5-87
Cleaning Exterior Lamps/Lenses.......................5-85
Cleaning Fabric/Carpet....................................5-83
Cleaning Glass Surfaces..................................5-84
Cleaning Interior Plastic Components
.................5-84
Cleaning Leather
............................................5-83
Cleaning the Mirror
.........................................2-30
Cleaning the Top of the Instrument Panel
...........5-84
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2003 - Sierra Denali

Driving (cont.)
Drunken....................................................... 4-2
Freeway.....................................................4-36
Hill and Mountain Roads..............................4-38
In Rain and on Wet Roads...........................4-32
Winter........................................................4-40
Driving Across an Incline..................................4-27
Driving Downhill..............................................4-25
Driving in Mud, Sand, Snow or Ice....................4-28
Driving in Water..............................................4-29
Driving On Grades..........................................4-59
Driving on Off-Road Hills.................................4-23
Driving on Snow or Ice....................................4-40
Driving Through Deep Standing Water...............4-34
Driving Through Flowing Water.........................4-34
Driving Uphill..................................................4-24
Driving with a Trailer.......................................4-58
Dual Automatic Climate Control System.............3-18
E
Easy Exit Seat...............................................2-42
Electrical System
Add-On Equipment......................................5-91
Fuses and Circuit Breakers...........................5-91
Power Windows and Other Power Options......5-91
Windshield Wiper Fuses...............................5-91
Electrochromic Mirror Operation........................2-28
Emissions Inspection and Maintenance
Programs...................................................3-39Engine
Air Cleaner/Filter
.........................................5-18
Battery
.......................................................5-39
Check and Service Engine Soon Light
............3-37
Compartment Overview
................................5-12
Coolant
......................................................5-23
Coolant Heater
............................................2-18
Coolant Temperature Gage
...........................3-36
Cooling System Inspection
............................6-14
Exhaust
.....................................................2-26
Fan Noise
..................................................5-34
Oil
.............................................................5-13
Overheating
................................................5-26
Starting
......................................................2-17
ENGINE COOLANT HOT
.................................3-52
Engine Coolant Level Check
.............................6-10
Engine Hour Meter Display
...............................3-26
Engine Oil Additives
........................................5-16
Engine Oil Level Check
...................................6-10
ENGINE OVERHEATED
..................................3-52
Entry Lighting
.................................................3-15
Environmental Concerns
..................................4-20
Erasing HomeLink
®Buttons
..............................2-38
Exit Lighting
...................................................3-15
Express-Down Windows
...................................2-12
Extender, Safety Belt
.......................................1-28
Exterior Lamps
...............................................3-11
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2003 - Sierra Denali

H
Hazard Warning Flashers................................... 3-4
Head Restraints............................................... 1-5
Headlamp High/Low Beam Changer.................... 3-6
Headlamps....................................................5-48
Bulb Replacement.......................................5-48
Front Turn Signal, Sidemarker and Daytime
Running Lamps........................................5-49
Halogen Bulbs............................................5-48
Pickup Box Identification and Fender
Marker Lamps.........................................5-54
Roof Marker Lamps.....................................5-51
Heated Seats................................................... 1-3
Heating.........................................................3-22
Highway Hypnosis...........................................4-38
Hill and Mountain Roads..................................4-38
Hitches..........................................................4-57
HomeLink
®Transmitter, Programming................2-35
HomeLink®Transmitter....................................2-35
Hood
Checking Things Under................................5-10
Release.....................................................5-10
Horn ............................................................... 3-5
How to Add Coolant to the Coolant Surge Tank......5-30
How to Add Fluid............................................5-22
How to Check........................................5-20, 5-57
How to Check Lubricant...................................5-46
How to Check Power Steering Fluid..................5-35How to Inspect...............................................5-18
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-12
Hydroplaning..................................................4-33
I
If No Steam Is Coming From Your Engine..........5-28
If Steam Is Coming From Your Engine...............5-27
If the Light is Flashing.....................................3-38
If the Light Is On Steady.................................3-38
If You Are Stuck in Sand, Mud, Ice or Snow.......4-44
If You Do Decide To Pull A Trailer.....................4-53
If You’re Caught in a Blizzard...........................4-42
Ignition Positions.............................................2-16
Ignition Transmission Lock Check......................6-13
Illuminated Visor Vanity Mirrors.........................2-13
Infants and Young Children, Restraints...............1-31
Inflation -- Tire Pressure..................................5-57
Inspection
Brake System
.............................................6-15
Engine Cooling System
................................6-14
Exhaust System
..........................................6-14
Fuel System
...............................................6-14
Part C - Periodic Maintenance
.......................6-14
Steering and Suspension
..............................6-14
Transfer Case and Front Axle
(All-Wheel Drive)
......................................6-15
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2003 - Sierra Denali