2003 GMC SONOMA engine coolant

Keys...............................................................2-3
Remote Keyless Entry System.........................2-4
Remote Keyless Entry System Operation...........2-5
Doors and Locks.............................................2-8
Door Locks....................................................2-8
Power Door Locks..........................................2-9
Programmable Automatic Door Locks................2-9
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-11
Leaving Your Vehicle....................................2-11
Third Door...................................................2-12
Tailgate.......................................................2-12
Windows........................................................2-14
Manual Windows..........................................2-15
Power Windows............................................2-15
Swing-Out Windows......................................2-16
Sliding Rear Window.....................................2-16
Sun Visors...................................................2-16
Theft-Deterrent Systems..................................2-17
Content Theft-Deterrent.................................2-17
Passlock
®....................................................2-19Starting and Operating Your Vehicle................2-20
New Vehicle Break-In....................................2-20
Ignition Positions..........................................2-20
Starting Your Engine.....................................2-22
Engine Coolant Heater..................................2-24
Automatic Transmission Operation...................2-25
Manual Transmission Operation......................2-28
Four-Wheel Drive..........................................2-29
Parking Brake..............................................2-32
Shifting Into Park (P).....................................2-33
Shifting Out of Park (P).................................2-35
Parking Your Vehicle.....................................2-36
Parking Over Things That Burn.......................2-36
Engine Exhaust............................................2-37
Running Your Engine While You Are Parked. . . .2-38
Mirrors...........................................................2-39
Manual Rearview Mirror.................................2-39
Automatic Dimming Rearview Mirror................2-39
Outside Manual Mirror...................................2-39
Outside Power Mirrors...................................2-40
Outside Convex Mirror...................................2-40
Outside Heated Mirrors..................................2-41
Section 2Features and Controls
2-1
2003 - Sonoma OM

Engine Coolant Heater
Your vehicle may be equipped with this feature.
In very cold weather, 0°F(–18°C) or colder, the engine
coolant heater can help. You’ll get easier starting and
better fuel economy during engine warm-up. Usually, the
coolant heater should be plugged in a minimum of four
hours prior to starting your vehicle. At temperatures
above 32°F(0°C), use of the coolant heater is not
required.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located in the engine compartment behind
the underhood fuse block on the driver’s side of
the vehicle.
3. Plug it into a normal, grounded 110–volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause afire. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord
won’t reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you don’t, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer in the area where you’ll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
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2003 - Sonoma OM

Instrument Panel Overview...............................3-2
Hazard Warning Flashers................................3-3
Other Warning Devices...................................3-4
Horn .............................................................3-4
Tilt Wheel.....................................................3-4
Turn Signal/Multifunction Lever.........................3-5
Exterior Lamps.............................................3-10
Interior Lamps..............................................3-14
Accessory Power Outlets...............................3-15
Ashtrays and Cigarette Lighter........................3-16
Climate Controls............................................3-17
Climate Control System.................................3-17
Outlet Adjustment.........................................3-19
Warning Lights, Gages and Indicators.............3-20
Instrument Panel Cluster................................3-21
Speedometer and Odometer...........................3-23
Trip Odometer..............................................3-23
Tachometer.................................................3-23
Safety Belt Reminder Light.............................3-23
Air Bag Readiness Light................................3-24
Air Bag Off Light..........................................3-24
Charging System Light..................................3-26
Voltmeter Gage............................................3-26
Up-Shift Light...............................................3-27
Brake System Warning Light..........................3-27Anti-Lock Brake System Warning Light.............3-28
Engine Coolant Temperature Gage..................3-29
Malfunction Indicator Lamp.............................3-29
Oil Pressure Gage........................................3-32
Security Light...............................................3-33
Service Four-Wheel Drive Warning Light..........3-34
Check Gages Warning Light...........................3-34
Fuel Gage...................................................3-35
Low Fuel Warning Light.................................3-35
Audio System(s).............................................3-36
Setting the Time for Radios without Radio
Data Systems (RDS)..................................3-36
Setting the Time for Radios with Radio
Data Systems (RDS)..................................3-37
AM-FM Radio...............................................3-37
Radio with CD..............................................3-40
Radio with Cassette and CD..........................3-47
Radio with Six-Disc CD.................................3-56
Theft-Deterrent Feature (Non-RDS Radios).......3-67
Theft-Deterrent Feature (RDS Radios).............3-67
Understanding Radio Reception......................3-67
Care of Your Cassette Tape Player.................3-68
Care of Your CDs
.........................................3-69
Care of Your CD Player
................................3-69
Fixed Mast Antenna
......................................3-69
Section 3 Instrument Panel
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2003 - Sonoma OM

Heating
Turn the center knob clockwise or counterclockwise to
raise or lower the temperature on the inside of your
vehicle.
When it’s cold outside 0°F(−18°C) or lower, use the
engine coolant heater, if equipped, to provide warmer air
faster to your vehicle. An engine coolant heater warms
the coolant that the engine uses to provide heat to
warm the inside of your vehicle. For more information,
seeEngine Coolant Heater on page 2-24.
Cooling
On hot days, open the windows to let hot inside air
escape; then close them. This helps to reduce the time
it takes for your vehicle to cool down. It also helps
the system to operate more efficiently.
A/C (Air Conditioning):Turn the knob to the A/C
position to turn the air-conditioning system on or
off. When the system is on, this setting cools and
dehumidies the air entering your vehicle and directs
it through theoor outlets as well as the instrument
panel outlets.
MAX A/C (Maximum Air Conditioning):This mode
recirculates much of the air inside your vehicle so
it cools quickly. It directs most of the air through the
instrument panel outlets and a small amount through
theoor outlets.
-(Blend):Use this mode to direct half the air to the
windshield and half to theoor outlets. Close the
center outlets to help defrost the side windows more
quickly. In this mode, the system will automatically force
outside air into your vehicle and it will also run the
air-conditioning compressor, unless it falls below the
temperature at which air conditioning is effective.
You may notice a slight change in engine performance
when the air-conditioning compressor shuts off and
turns on again. This is normal. The system is designed
to make adjustments to help with fuel economy while
still maintaining the selected temperature.
For quick cool down on hot days, do the following:
1. Select A/C.
2. Select the coolest temperature.
3. Select the highest fan speed.
On cool, but sunny days, the sun may warm the upper
part of your body, but the lower part may not be
warm enough. To remedy this, do the following:
1. Select the bi-level mode.
2. Select the temperature.
3. Select the fan speed.
The air-conditioning system removes moisture from the
air, so you may sometimes notice a small amount of
water dripping underneath your vehicle while idling
or after turning off the engine. This is normal.
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2003 - Sonoma OM

Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
If the gage pointer moves into the red area, your engine
is too hot!
It means that your engine coolant has overheated.
If you have been operating your vehicle under normal
driving conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible.
SeeEngine Overheating on page 5-28for more
information.
Malfunction Indicator Lamp
Service Engine Soon Light in the
United States or Check Engine Light
in Canada
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. United States
Canada
United StatesCanada
3-29
2003 - Sonoma OM

Service Four-Wheel Drive Warning
Light
If you have this light,
it should come on briey
when you turn on the
ignition, as a check
to show you it is working.
The SERVICE 4WD light comes on to indicate that
there may be a problem with the four-wheel drive system
and service is required. Malfunctions can be indicated
by the system before any problem is apparent,
which may prevent serious damage to the vehicle.
This system is also designed to assist your service
technician in correctly diagnosing a malfunction.
Check Gages Warning Light
The CHECK GAGES
light will come on briey
when you are starting
the engine.
If this light comes and stays on while you are driving,
check your coolant temperature and engine oil pressure
gages to see if they are in the warning zones.
3-34
2003 - Sonoma OM

Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you should use
THIRD (3) when towing a trailer. Operating your
vehicle in THIRD (3) when towing a trailer will minimize
heat buildup and extend the life of your transmission.
Or, if you have a manual transmission, it’s better not to
use FIFTH (5). Just drive in FOURTH (4) (or, as you
need to, a lower gear).
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P)
(or the manual transmission out of gear and the parking
brake applied) for a few minutes before turning the
engine off. If you do get the overheat warning,
seeEngine Overheating on page 5-28.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet, or into gear for a manual
transmission. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4-59
2003 - Sonoma OM

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of
Your Vehicle..............................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Specifications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-5
Fuels in Foreign Countries...............................5-6
Filling Your Tank............................................5-6
Filling a Portable Fuel Container.......................5-8
Checking Things Under
the Hood......................................................5-8
Hood Release................................................5-9
Engine Compartment Overview.......................5-10
Engine Oil...................................................5-13
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid
.........................5-20
Manual Transmission Fluid
.............................5-23
Hydraulic Clutch
...........................................5-24Engine Coolant.............................................5-25
Radiator Pressure Cap..................................5-27
Engine Overheating.......................................5-28
Cooling System............................................5-30
Engine Fan Noise.........................................5-36
Power Steering Fluid.....................................5-37
Windshield Washer Fluid................................5-38
Brakes........................................................5-39
Battery........................................................5-42
Jump Starting...............................................5-43
Rear Axle.......................................................5-47
Four-Wheel Drive............................................5-48
Front Axle......................................................5-49
Bulb Replacement..........................................5-50
Halogen Bulbs..............................................5-50
Headlamps..................................................5-50
One-Piece Front Turn Signal Lamps................5-52
Two-Piece Front Turn Signal Lamps................5-53
Center High-Mounted Stoplamp (CHMSL).........5-54
Taillamps.....................................................5-55
Replacement Bulbs.......................................5-55
Section 5 Service and Appearance Care
5-1
2003 - Sonoma OM