1999 CHEVROLET SUBURBAN service

yellowblue
2-23
CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P). You or someone else could be
seriously injured. Be sure to set the parking
brake before placing the transfer case in
NEUTRAL. See ªParking Brakeº in the Index.
NEUTRAL: Shift the vehicle's transfer case to neutral
only when towing your vehicle. See ªRecreational
Vehicle Towingº or ªTowing Your Vehicleº in the Index
for more information.
Indicator lights in the switches show 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 to your dealer for
service. An indicator light will flash while shifting the
transfer case. It will remain illuminated when the shift is
complete. If for some reason the transfer case cannot make
a requested shift, it will return to the last chosen setting.
If the SERVICE 4WD light stays on, you should take
your vehicle to your dealer for service. See ªService
4WDº in the Index for further information.Shifting to 4HI or AUTO 4WD
Press and release the 4HI or AUTO 4WD switch. This
can be done at any speed, and the indicator light will
flash while shifting. It will remain illuminated when the
shift is completed.
Shifting to 2HI
Press and release the 2HI switch. This can be done at
any speed.
Shifting to 4LO
To shift to 4LO, the vehicle's engine must be running
and the vehicle must be stopped or moving less
than 3 mph (4.8 km/h) with the transmission in
NEUTRAL (N). 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 switch.
You must wait for the 4LO indicator light to stop
flashing and remain illuminated before shifting your
transmission into gear.
If the 4LO switch 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 less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds the
transfer case will return to the setting last chosen.

yellowblue
2-65
The transmitter will learn and transmit the frequencies
of most current transmitters and is powered by your
vehicle's battery and charging system.
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) this device may not cause harmful interference,
and (2) this device must accept any interference
received, including interference that may cause
undesired operation.
This device complies with RSS
-210 of Industry Canada.
Operation is subject to the following two conditions:
(1) this device may not cause interference, and (2) this
device must accept any interference, including
interference that may cause undesired operation of
the device.
Changes and modifications to this system by other than
an authorized service facility could void authorization to
use this equipment.
Programming the Transmitter
Do not use the transmitter with any garage door opener
that does not have the ªstop and reverseº feature. This
includes any garage door opener model manufactured
before April 1, 1982.
Be sure that people and objects are clear of the garage
door you are programming.
Your vehicle's engine should be turned off while
programming the transmitter. Follow these steps to
program up to three channels.
1. If you have not previously programmed a universal
channel, proceed to Step 2. Otherwise, hold down
the two outside buttons on the universal transmitter
until the red light begins to flash rapidly
(approximately 20 seconds). Then release the
buttons. This procedure initializes the memory and
erases any previous settings for all three channels.
2. Hold the end of the hand
-held transmitter against the
bottom surface of the universal transmitter so that
you can still see the red light.

yellowblue
2-73 Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows AIR BAG. The system checks the
air bag's electrical system for malfunctions. The light
tells you if there is an electrical problem. The system
check includes the air bag sensors, the air bag modules,
the wiring and the crash sensing and diagnostic module.
For more information on the air bag system, see ªAir
Bagº in the Index.
This light will come on
when you start your engine,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
engine or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.
The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Charging System Warning Light
The charging system
warning light should come
on briefly when you turn on
the ignition, before starting
the engine, as a check to
show you it is working.
After the engine starts, the light should go out. If it stays
on or comes on while you are driving, you may have a
problem with your charging system. It could indicate a
problem with the generator drive belt, or some other
charging system problem. Have it checked right away.
Driving while this light is on could drain your battery.
If you must drive a short distance with this light on, it
helps to turn off all your accessories, such as the radio
and the air conditioner.

yellowblue
2-74 Voltmeter
When your engine is not
running, but the ignition is
in the RUN position, 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.
Brake System Warning Light
When the ignition is on, the brake system warning light
will come on when you set your parking brake. The light
will stay on if your parking brake doesn't release fully.
If it stays on after your parking brake is fully released, it
means you have a brake problem.
Your vehicle's hydraulic brake system is divided into
two parts. If one part isn't working, the other part can
still work and stop you. For good braking, though, you
need both parts working well.
If the warning light comes on, there could be a brake
problem. Have your brake system inspected right away.

yellowblue
2-75
This light should come on
briefly when you turn the
ignition key to RUN. If it
doesn't come on then,
have it fixed so it will be
ready to warn you if there's
a problem.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the floor.
It may take longer to stop. If the light is still on, have the
vehicle towed for service. (See ªTowing Your Vehicleº
in the Index.)
CAUTION:
Your brake system may not be working properly
if the brake system warning light is on. Driving
with the brake system warning light on can lead
to an accident. If the light is still on after you've
pulled off the road and stopped carefully, have
the vehicle towed for service.
Anti-Lock Brake System Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on for
several seconds. That's
normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake system
warning light isn't on, you still have brakes, but you
don't have anti
-lock brakes. If the regular brake system
warning light is also on, you don't have anti
-lock brakes
and there's a problem with your regular brakes. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.

yellowblue
2-76 Engine Coolant Temperature Gage
This gage shows the engine
coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210
F (100
C) or less. If you are pulling a
load or going up hills, it is normal for the temperature to
fluctuate and approach the 260
F (160
C) mark. If the
gage reaches the 260
F (160
C) mark, it indicates that
the cooling system is working beyond its capacity.
The ªProblems on the Road,º section of this manual
shows what to do. See ªEngine Overheatingº in
the Index.
Malfunction Indicator Lamp (Service
Engine Soon Light) (Gasoline Engine)
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 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.

yellowblue
2-77
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 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
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.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is not
running. If the light doesn't come on, have it repaired.
This light will also come on during a malfunction in one
of two ways:

Light Flashing
-- A misfire condition has been
detected. A misfire increases vehicle emissions and
may damage the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.

Light On Steady
-- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis and
service may be required.
If the Light Is Flashing
The following may prevent more serious damage to
your vehicle:

Reducing vehicle speed.

Avoiding hard accelerations.

Avoiding steep uphill grades.

If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.

yellowblue
2-78
If the light stops flashing and remains on steady, see ªIf
the Light Is On Steadyº following.
If the light continues to flash, when it is safe to do so,
stop the vehicle. Find a safe place to park your vehicle.
Turn the key off, wait at least 10 seconds and restart the
engine. If the light remains on steady, see ªIf the Light
Is On Steadyº following. If the light is still flashing,
follow the previous steps, and drive the vehicle to your
dealer or qualified service center for service.
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.