2002 GMC SONOMA Fuel system

2-18
Passlock
Your vehicle is equipped with the Passlock
theft
-deterrent system.
Passlock is a passive theft
-deterrent system. Passlock
enables fuel if the ignition lock cylinder is turned with a
valid key. If a correct key is not used or the ignition lock
cylinder is tampered with, fuel is disabled.
During normal operation, the SECURITY light will go off
approximately five seconds after the key is turned to RUN.
If the engine stalls and the SECURITY light flashes,
wait about 10 minutes until the light stops flashing
before trying to restart the engine. Remember to release
the key from START as soon as the engine starts.
If the engine does not start after three tries, the vehicle
needs service.
If the engine is running and the SECURITY message
comes on, you will be able to restart the engine if you turn
the engine off. However, your Passlock system is not
working properly and must be serviced by your dealer.
Your vehicle is not protected by Passlock at this time. You
may also want to check the fuse (see ªFuses and Circuit
Breakersº in the Index). See your dealer for service.
In an emergency, call the GM Roadside Assistance
Center. See ªRoadside Assistanceº in the Index.
New Vehicle ªBreak-Inº
NOTICE:
Your vehicle doesn't need an elaborate
ªbreak
-in.º But it will perform better in the long
run if you follow these guidelines:

Keep your speed at 55 mph (88 km/h) or
less for the first 500 miles (805 km).

Don't drive at any one speed
-- fast or
slow
-- for the first 500 miles (805 km).
Don't make full
-throttle starts.

Avoid making hard stops for the first
200 miles (322 km) or so. During this time
your new brake linings aren't yet broken
in. Hard stops with new linings can mean
premature wear and earlier replacement.
Follow this breaking
-in guideline every
time you get new brake linings.

Don't tow a trailer during break
-in.
See ªTowing a Trailerº in the Index for
more information.

2-73 Voltmeter Gage
When your engine is not
running, but the ignition is
on (in RUN), this gage
shows your battery's state of
charge in DC volts.
When the engine is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power at
engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.You can only drive for a short time with the reading in
either warning zone. If you must drive, turn off all
unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Shift Light
You have the shift light if
you have a manual
transmission.
Shifting when the indicator light is on will help you get
the best fuel economy. See ªShift Lightº in the Index.

2-76 Malfunction Indicator Lamp (Service
Engine Soon Light in the United States or
Check Engine Light in Canada)
United States 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. The
SERVICE ENGINE SOON or 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:
Modifications 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 the SERVICE ENGINE SOON
OR CHECK ENGINE light to come on.
Modifications 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.

2-78
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. See ªFilling Your Tankº in the Index. 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 off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
ªFuelº in the Index. Poor fuel quality will cause your
engine not to run as efficiently as designed. You may
notice this as stalling after start
-up, stalling when you
put the vehicle into gear, misfiring, hesitation on
acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the light
to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least one
full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
have your dealer or qualified service center check the
vehicle. Your dealer has the proper test equipment and
diagnostic tools to fix any mechanical or electrical
problems that may have developed.

2-83 Low Fuel Light
This light comes on briefly
when you start your engine.
This light comes on when the fuel tank is low on fuel.
To turn it off, add fuel to the fuel tank. See ªFuelº in
the Index.
Driver Information Center (DIC) (If Equipped)
This system displays the outside air temperature,
compass direction and trip information in the
overhead console.
US/MET (United States/Metric): The US/MET
(United States/metric) button allows you to switch the
display between the English and metric system.
MODE: The MODE button can be used to toggle
between three modes of operation: OFF, COMP/TEMP
and TRIP.COMP/TEMP (Compass/Temperature): The
display provides the outside temperature and one of
eight compass readings to indicate the direction the
vehicle is facing.
Before you turn on the ignition and move the vehicle,
the temperature indicated will be the last outside
temperature recorded with the ignition on. If the outside
temperature is 37
F (3
C) or lower, the display will
toggle between the word ICE and the current
temperature every eight seconds. This is a warning to
the driver that road conditions may be icy, and that
appropriate precautions should be taken.
The compass is self
-calibrating, so it does not need to be
manually set. However, if ªCº (Calibration) is
displayed, the compass will need to be calibrated. You
may also place the compass in a noncalibrated mode by
pressing and holding the MODE and US/MET buttons
simultaneously while in the COMP/TEMP mode. After
about 10 seconds, the compass will display C and you
can release the buttons. Drive the vehicle in a complete
360
circle three times at a speed of less than 5 mph
(8 km/h), and the compass will function normally. Once
the calibration is complete, the display will return to a
compass reading.

2-84
Variance is the difference between magnetic north and
geographic north. In some areas, the difference between
the two can be great enough to cause false compass
readings. If this happens, follow these instructions to set
the variance for your particular location:
1. Find your location on the zone map earlier in this
section. Record your zone number.
2. Press and hold both the MODE and the US/MET
buttons in the COMP/TEMP mode.
3. After five seconds, the compass will acknowledge
the variation mode by displaying the current zone
number. When it does, release both buttons.
4. Press US/MET until your zone number appears on
the display.
5. Press MODE to enter your zone number. Your
variance is now set and the display will return to the
COMP/TEMP mode.TRIP: Once in the TRIP mode, pressing the
MODE button will step you through the following
TRIP functions:

AVG ECON (Average Economy): The average fuel
economy since the last reset is displayed.

INST ECON (Instantaneous Economy):
Instantaneous fuel economy for the last second of
driving is displayed.

RANGE: The display indicates the estimated
distance that can be travelled with the remaining fuel
in the tank, based on the fuel economy for the last
few hours of driving.

FUEL USED: The fuel used since the last reset is
displayed.

AVG SPEED (Average Speed): The average speed
since the last reset is displayed.
To reset the trip computer, press the MODE and
US/MET buttons simultaneously for at least two
seconds. All functions will be displayed briefly once the
system is reset. Reset can only be performed in the AVG
ECON, FUEL USED and AVG SPEED modes. All three
modes are reset simultaneously.

4-27 After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust system
for damage. Also, check the fuel lines and cooling
system for any leakage.
Your vehicle will require more frequent service due to
off
-road use. Refer to the Maintenance Schedule for
additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired
-- by alcohol or drugs, with night vision
problems, or by fatigue.

4-34
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 that first 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'll find 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 inflated 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?