service indicator GMC SONOMA 2002 Owner's Manual

2-32 Electronic Transfer Case (If Equipped)
The electronic transfer case
buttons are located to the
right of the steering wheel.
Use these buttons to shift into and out of four
-wheel
drive. You can choose among three driving settings:
2HI: This setting is for driving in most street and
highway situations. Your front axle is not engaged in
two
-wheel drive. When this lamp is lit, it is about
one
-half as bright as the others.4HI: This setting engages your front axle to help drive
your vehicle. Use 4HI when you need extra traction,
such as on snowy or icy roads, or in most off
-road
situations.
4LO: This setting also engages your front axle to give
you extra traction. You may never need 4LO. It sends
the maximum power to all four wheels. You might
choose 4LO if you were driving off
-road in sand, mud
or deep snow and climbing or descending steep hills.
Indicator lights in the buttons show you which setting
you are in. The indicator lights will come on briefly
when you turn on the ignition and one will stay on.
If the lights do not come on, you should take your
vehicle in for service. An indicator light will flash while
shifting. It will remain illuminated when the shift is
completed.
Shifting from 2HI to 4HI
Press and release the 4HI button. This can be done at
any speed, and the front axle will lock automatically.
Shifting from 4HI to 2HI
Press and release the 2HI button. This can be done at
any speed, and the front axle will unlock automatically.

2-33
Shifting from 2HI or 4HI to 4LO
To shift from 2HI or 4HI to 4LO, the vehicle must be
stopped or moving less than 3 mph (4.8 km/h) with the
transmission in NEUTRAL (N) in vehicles equipped
with an automatic transmission or the clutch pedal
engaged in vehicles equipped with a manual
transmission. The preferred method for shifting into
4LO is to have your vehicle moving 1 to 2 mph (1.6 to
3.2 km/h). Press and release the 4LO button. You must
wait for the 4LO indicator light to stop flashing and
remain illuminated before shifting your transmission
into gear or releasing the clutch pedal.
If the 4LO button is pressed when your vehicle is in gear
and/or moving, the 4LO indicator light will flash for
30 seconds and not complete the shift unless your vehicle is
moving slower than 3 mph (4.8 km/h) and the transmission
is in NEUTRAL (N) or the clutch pedal engaged.
On automatic transmission equipped vehicles, if your
transfer case does not shift into 4LO, your transmission
indicator switch may require adjustment. With your
transmission in NEUTRAL (N), press and release the
4LO button. While the 4LO indicator light is flashing,
shift your transmission into PARK (P). Wait until the
4LO indicator light remains illuminated before shifting
your transmission into gear. This will get you into 4LO,
but you should take your vehicle in for service to restore
normal operation.Shifting from 4LO to 4HI or 2HI
To shift from 4LO to 4HI or 2HI, your vehicle must be
stopped or moving less than 3 mph (4.8 km/h) with the
transmission in NEUTRAL (N) or the clutch pedal
engaged. The preferred method for shifting out of 4LO
is to have your vehicle moving 1 to 2 mph (1.6 to
3.2 km/h). Press and release the 4HI button. You must
wait for the 4HI indicator light to stop flashing and
remain illuminated before shifting your transmission
into gear or releasing the clutch pedal.
If the 4HI button is pressed when your vehicle is in
gear and/or moving, the 4HI indicator light will flash for
30 seconds but not complete the shift unless the vehicle
is moving slower than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N) or the clutch pedal
engaged.
On automatic transmission equipped vehicles, if your
transfer case does not shift into 4HI, your transmission
indicator switch may require adjustment. With your
transmission in NEUTRAL (N), press and release the
4HI button. While the 4HI indicator light is flashing,
shift your transmission into PARK (P). Wait until the
4HI indicator light remains illuminated before shifting
your transmission into gear. This will get you into 4HI,
but you should take your vehicle in for service to restore
normal operation.

2-72
CAUTION:
If the air bag readiness light ever comes on when
you have turned off the air bag, it means that
something may be wrong with the air bag system.
The right front passenger's air bag could inflate
even though the switch is off. If this ever
happens, don't let anyone whom the national
government has identified as a member of a
passenger air bag risk group sit in the right front
passenger's position (for example, don't secure a
rear
-facing child restraint in your vehicle) until
you have your vehicle serviced.
Charging System Indicator Light
The charging system light
will come on briefly when
you turn on the ignition,
but the engine is not
running, as a check to
show you it is working.
It should go out once the engine is running. If it stays
on, or comes on while you are driving, you may have a
problem with the charging system. It could indicate that
you have problems with a generator drive belt, or
another electrical problem. Have it checked right away.
Driving while this light is on could drain your battery.
If you must drive a short distance with the light on, be
certain to turn off all your accessories, such as the radio
and air conditioner.

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.

3-63
3. Press and hold the TAPE AUX button for five
seconds. The tape symbol on the display will flash
for two seconds.
4. Insert the scrubbing action cleaning cassette.
5. Eject the cleaning cassette after the manufacturer's
recommended cleaning time.
When the cleaning cassette has been ejected, the broken
tape detection feature is active again.
You may also choose a non
-scrubbing action, wet-type
cleaner which uses a cassette with a fabric belt to clean
the tape head. This type of cleaning cassette will not
eject on its own. A non
-scrubbing action cleaner may
not clean as thoroughly as the scrubbing type cleaner.
The use of a non
-scrubbing action, dry-type cleaning
cassette is not recommended.
After you clean the player, press and hold the EJECT
button for five seconds to reset the CLN indicator. The
radio will display
--- to show the indicator was reset.
Cassettes are subject to wear and the sound quality
may degrade over time. Always make sure the cassette
tape is in good condition before you have your tape
player serviced.
Care of Your Remote Cassette Tape Player
A tape player that is not cleaned regularly can cause
reduced sound quality, ruined cassettes or a damaged
mechanism. Cassette tapes should be stored in their
cases away from contaminants, direct sunlight and
extreme heat. If they aren't, they may not operate
properly or may cause failure of the tape player.
Your remote tape player should be cleaned regularly
after every 50 hours of use. Your radio may display
CLN to indicate that you have used your remote cassette
tape player for 50 hours without resetting the tape clean
timer. If this message appears on the display, your
remote cassette tape player needs to be cleaned. It will
still play tapes, but you should clean it as soon as
possible to prevent damage to your tapes and player.
The recommended cleaning method for your remote
cassette tape player is the use of a scrubbing action,
non
-abrasive cleaning cassette with pads which scrub
the tape head as the hubs of the cleaner cassette turn.
The recommended cleaning cassette is available through
your dealer (GM Part No. 12344789).

6-5
Fuels containing MMT can reduce the life of spark
plugs and the performance of the emission control
system may be affected. The malfunction indicator lamp
may turn on. If this occurs, return to your authorized
GM dealer for service.
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work properly.
You should not have to add anything to your fuel.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage plastic and rubber parts.
That damage wouldn't be covered under your
warranty.
Fuel E-85 (85% Ethanol)
The 8th digit of your vehicle identification number
(VIN) shows the code letter or number that identifies
your engine. You will find the VIN at the top left of the
instrument panel. See ªVehicle Identification Numberº
in the Index.
If your vehicle has the 2200 L4 engine (VIN Code 5),
you may use either regular unleaded gasoline or ethanol
fuel containing up to 85% ethanol (E
-85); also see
ªFuel (Gasoline)º listed previously. If your vehicle has
the 4.3L V6 engine use only regular unleaded gasoline.
Only vehicles with the 2200 L4 engine (VIN Code 5)
may use 85% ethanol fuel (E
-85).
Many service stations will not have an 85% ethanol
fuel (E
-85) pump available. The U. S. Department
of Energy has an alternative fuels website
(http://afdcmap.nrel.gov/nrel/) that can help you find E
-85
fuel. Those stations that do have E
-85 should have a label
indicating ethanol content. Do not use the fuel if the
ethanol content is greater than 85%. Your vehicle may not
operate properly if the ethanol content is greater than 85%.
At a minimum, E
-85 should meet
ASTM Specification D 5798.

6-36
NOTICE:

Using the wrong fluid can badly damage
brake system parts. For example, just a few
drops of mineral
-based oil, such as engine
oil, in your brake system can damage brake
system parts so badly that they'll have to be
replaced. Don't let someone put in the
wrong kind of fluid.

If you spill brake fluid on your vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake fluid
on your vehicle. If you do, wash it off
immediately. See ªAppearance Careº in
the Index.
Brake Wear
If you have four-wheel drive, your vehicle has
four
-wheel disc brakes. If not, your vehicle has front
disc brakes and rear drum brakes.
Disc brake pads have built
-in wear indicators that make
a high
-pitched warning sound when the brake pads are
worn and new pads are needed. The sound may come
and go or be heard all the time your vehicle is moving
(except when you are pushing on the brake pedal
firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.