2003 GMC SONOMA ECU

Remote Oil Filter (Four-Wheel Drive)
The access door for the
remote oilfilter is in the
steering linkage shield
assembly located under
the radiator support.
Turn the screw to unlock
or lock the door. Make
sure if you open the door,
it is securely closed
when you arefinished.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don’t let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it in
the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by taking it
to a place that collects used oil. If you have a problem
properly disposing of your used oil, ask your dealer, a
service station or a local recycling center for help.
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2003 - Sonoma OM

Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km).
Any time you notice unusual wear, rotate your tires as
soon as possible and check wheel alignment. Also
check for damaged tires or wheels. SeeWhen It Is Time
for New Tires on page 5-61andWheel Replacement
on page 5-65for more information.
Make sure the spare tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If it moves,
use the wheel wrench to tighten the cable. See
Changing a Flat Tire on page 5-68.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. Thefirst rotation
is the most important. See“Part A: Scheduled
Maintenance Services,”in Section 6, for scheduled
rotation intervals.When rotating your tires, always use one of the correct
rotation patterns shown here.
If your vehicle has a compact spare tire or a spare tire
that does not match your vehicle’s regular road tires
and wheels in size and type, do not include the spare
in the tire rotation.
5-60
2003 - Sonoma OM

CAUTION: (Continued)
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your wheels.
If you dond traction devices that willt,
install them on the rear tires.
Notice:If your vehicle has a tire size other than
P235/75R15, P235/70R15, P235/55R16 or
31x10.50R15LT/C, use tire chains only where legal
and only when you must. Use only SAE Class″S″
type chains that are the proper size for your tires.
Install them on the drive axle tires (four-wheel-drive
vehicles can use chains on both axles) and tighten
them as tightly as possible with the ends securely
fastened. Drive slowly and follow the chain
manufacturer’s instructions. If you can hear the
chains contacting your vehicle, stop and retighten
them. If the contact continues, slow down until it
stops. Driving too fast or spinning the wheels with
chains on will damage your vehicle.
If a Tire Goes Flat
It’s unusual for a tire to“blowout”while you’re driving,
especially if you maintain your tires properly. If air goes
out of a tire, it’s much more likely to leak out slowly.
But if you should ever have a“blowout”, here are a few
tips about what to expect and what to do:
If a front tire fails, theflat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheelfirmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you’d use
in a skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop—well off the road if possible.
If a tire goesflat, the next part shows how to use your
jacking equipment to change aflat tire safely.
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2003 - Sonoma OM

4. Raise the tire fully against the underside of the
vehicle by turning the wrench clockwise until you
hear two clicks or feel it skip twice. The spare
tire hoist cannot be overtightened.
5. Make sure the tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If the tire
moves, use the wheel wrench to tighten the cable.Return the jack, wheel wrench and wheel blocks to the
proper location behind the seat. Secure the items.
A. Wheel Wrench
B. Bracket
C. Jacking Instructions (Roll and place instructions
behind the bracket after the tools are installed.)
D. Bolt Location
E. Wheel Blocks
F. Nut
G. Rubber Band
H. Jack Position
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2003 - Sonoma OM

Also look for any opened or broken air bag coverings,
and have them repaired or replaced. (The air bag
system does not need regular maintenance.)
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace
blade inserts that appear worn or damaged or that
streak or miss areas of the windshield. Also see
Cleaning the Outside of Your Vehicle on page 5-82.
Spare Tire Check
At least twice a year, after the monthly ination check of
the spare tire determines that the spare is inated to
the correct tire ination pressure, make sure that
the spare tire is stored securely. Push, pull, and then try
to rotate or turn the tire. If it moves, use the wheel
wrench to tighten the cable. SeeChanging a Flat Tire
on page 5-68.
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. SeePart D: Recommended Fluids and
Lubricants on page 6-33.
Manual Transmission Check
Check the transmissionuid level; add if needed.
SeeManual Transmission Fluid on page 5-23. Check
for leaks. Auid leak is the only reason foruid
loss. Have the system inspected and repaired if needed.
Automatic Transmission Check
Check the transmissionuid level; add if needed.
SeeAutomatic Transmission Fluid on page 5-20.Auid
loss may indicate a problem. Check the system and
repair if needed.
Hydraulic Clutch System Check
Check theuid level in the clutch reservoir. See
Hydraulic Clutch on page 5-24.
Auid loss in this system could indicate a problem.
Have the system inspected and repaired at once.
At Least Four Times a Year
Tailgate Lubrication Service
Lubricate tailgate latch bolt, handle assembly pivot
points, and hinges with lubricant recommended
in Part D.
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2003 - Sonoma OM

Care of
Safety Belts................................................5-82
Your Cassette Tape Player............................3-68
Your CD Player...........................................3-69
Your CDs ...................................................3-69
Cassette Tape Messages.................................3-54
Cassette Tape Player Service...........................6-26
Center High-Mounted Stoplamp (CHMSL)...........5-54
Center Passenger Position, Safety Belts.............1-23
Chains, Tires..................................................5-66
Charging System Light....................................3-26
Check
Engine Light...............................................3-29
Gages Warning Light
...................................3-34
Checking Brake Fluid
......................................5-40
Checking Coolant
............................................5-26
Checking Engine Oil
........................................5-13
Checking the Fluid Level
..................................5-21
Checking Things Under the Hood
....................... 5-8
Checking Your Restraint Systems
......................1-64
Chemical Paint Spotting
...................................5-85
Child Restraints
Child Restraint Systems
...............................1-36
Infants and Young Children
...........................1-32
Lower Anchorages and Top Tethers for
Children (LATCH System)
..........................1-44
Older Children
.............................................1-30Child Restraints (cont.)
Securing a Child Restraint Designed for
the LATCH System...................................1-46
Securing a Child Restraint in a Center
Seat Position...........................................1-49
Securing a Child Restraint in a Rear
Outside Seat Position...............................1-46
Securing a Child Restraint in the Right
Front Seat Position...................................1-49
Top Strap...................................................1-41
Top Strap Anchor Location............................1-43
Where to Put the Restraint...................1-39, 1-40
Cigarette Lighter.............................................3-16
Cleaning
Inside of Your Vehicle..................................5-79
Outside of Your Vehicle................................5-82
Underbody Maintenance...............................5-85
Weatherstrips..............................................5-82
Cleaning Exterior Lamps/Lenses.......................5-83
Cleaning the Mirror.........................................2-39
Cleaning the Photocells...................................2-39
Climate Control System...................................3-17
Outlet Adjustment........................................3-19
Clutch, Hydraulic.............................................5-24
Compact Disc Messages.................3-46, 3-56, 3-67
Compact Spare Tire........................................5-78
Content Theft-Deferrent....................................2-17
Control of a Vehicle.......................................... 4-5
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2003 - Sonoma OM

Coolant
Engine Temperature Gage............................3-29
Heater, Engine............................................2-24
Cooling.........................................................3-18
Cooling System..............................................5-30
Crew Cab
®....................................................1-46
Cruise Control.................................................. 3-8
Current and Past Model Order Forms................7-10
Customer Assistance Information
Courtesy Transportation.................................. 7-7
Customer Assistance for Text Telephone (TTY)
Users....................................................... 7-3
Customer Assistance Offices........................... 7-4
Customer Satisfaction Procedure..................... 7-2
GM Mobility Program for Persons with
Disabilities................................................ 7-5
Reporting Safety Defects to General Motors...... 7-9
Reporting Safety Defects to the Canadian
Government.............................................. 7-9
Reporting Safety Defects to the United States
Government.............................................. 7-8
Roadside Assistance Program......................... 7-5
Service Publications Ordering Information......... 7-9
D
Daytime Running Lamps..................................3-12
Defensive Driving............................................. 4-2
Defogging and Defrosting.................................3-19Dinghy Towing................................................4-43
Directing the Airflow ........................................3-17
Doing Your Own Service Work........................... 5-3
Dolly Towing..................................................4-44
Dome Lamp ...................................................3-15
Door
Locks.......................................................... 2-8
Power Door Locks......................................... 2-9
Programmable Automatic Door Locks............... 2-9
Rear Door Security Locks.............................2-11
Third Door..................................................2-12
Driver
Position, Safety Belt.....................................1-16
Driver Information Center (DIC).........................2-46
Driving
At Night.....................................................4-27
City ...........................................................4-31
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Freeway.....................................................4-32
Hill and Mountain Roads..............................4-34
In Rain and on Wet Roads...........................4-28
Winter........................................................4-36
Driving Across an Incline..................................4-22
Driving Downhill..............................................4-21
Driving in Mud, Sand, Snow or Ice....................4-25
Driving in Water..............................................4-26
Driving On Grades
..........................................4-59
Driving on Off-Road Hills
.................................4-18
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2003 - Sonoma OM

Instrument Panel Brightness.............................3-14
Instrument Panel Fuse Block............................5-89
Interior Lamps................................................3-14
Interior Plastic Components..............................5-81
J
Jump Seat.....................................................1-10
Jump Starting.................................................5-43
K
Key Lock Cylinders Service..............................6-28
Key Release Button........................................2-21
Keyless Entry System....................................... 2-4
Keys............................................................... 2-3
L
Lamps
Exterior......................................................3-10
Interior.......................................................3-14
Lamps On Reminder.......................................3-12
Lap Belt................................................1-23, 1-25
Lap-Shoulder Belt...........................................1-16LATCH System
Child Restraints
...........................................1-44
Securing a Child Restraint Designed for the
LATCH System
........................................1-46
Latches, Seatback
............................................ 1-8
Leather
.........................................................5-81
Leaving Your Vehicle
.......................................2-11
Leaving Your Vehicle With the Engine Running
. . . 2-34
Light
Air Bag Off
.................................................3-24
Air Bag Readiness
.......................................3-24
Anti-Lock Brake System Warning
...................3-28
Brake System Warning
.................................3-27
Charging System
.........................................3-26
Check Gages Warning
.................................3-34
Low Fuel Warning
.......................................3-35
Malfunction Indicator
....................................3-29
Safety Belt Reminder
...................................3-23
Security
.....................................................3-33
Service Four-Wheel-Drive Warning Light
.........3-34
Up-Shift
.....................................................3-27
Loading Your Vehicle
.......................................4-46
Loading Your Vehicle for Off-Road Driving
..........4-14
Locking Rear Axle
............................................ 4-7
Lockout Protection
..........................................2-11
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2003 - Sonoma OM