2002 GMC ENVOY four wheel drive

2-89
Service Four-Wheel-Drive Warning Light
(If Equipped)
United States Canada
This light should come on briefly 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 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 Light
United States Canada
The CHECK GAGES light will come on briefly when
you are starting the engine.
If the light comes on 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.

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Here are four things that some owners ask about.
None of these show a problem with your fuel gage:

At the gas station, the gas pump shuts off before the
gage reads full.

It takes a little more or less fuel to fill up than the
gage indicated. For example, the gage may have
indicated the tank was half full, but it actually took a
little more or less than half the tank's capacity to fill
the tank.

The gage moves a little when you turn a corner or
speed up.

The gage doesn't go back to empty when you turn
off the ignition.
Low Fuel Light
The light next to the fuel gage will come on briefly
when you are starting the 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)
The DIC display is located on the instrument panel
cluster above the steering wheel. The DIC can display
information such as the trip odometer, fuel economy and
personalization features.
A.Trip Information: This button will display the
odometer, trip odometer and the timer.
B.Fuel Information: This button will display the
current range, average fuel economy, instant fuel
economy and engine oil life.
C.Personalization: This button will change personal
options available on your vehicle.
D.Select: This button resets certain functions and turns
off or acknowledges messages on the DIC.

4-
4-1
Section 4 Your Driving and the Road
Here you'll find information about driving on different kinds of roads and in varying weather conditions.
We've also included many other useful tips on driving.
4
-2 Defensive Driving
4
-3 Drunken Driving
4
-6 Control of a Vehicle
4
-6 Braking
4
-9 Traction Assist System (TAS)
(Two
-Wheel Drive Only)
4
-11 Steering
4
-13 Off-Road Recovery
4
-13 Passing
4
-15 Loss of Control
4
-16 Off-Road Driving with Your
Four
-Wheel-Drive Vehicle4
-30 Driving at Night
4
-32 Driving in Rain and on Wet Roads
4
-35 City Driving
4
-36 Freeway Driving
4
-37 Before Leaving on a Long Trip
4
-38 Highway Hypnosis
4
-38 Hill and Mountain Roads
4
-40 Winter Driving
4
-44 Recreational Vehicle Towing
4
-47 Loading Your Vehicle
4
-50 Adding a Snow Plow or Similar Equipment
4-50 Towing a Trailer

4-16
Off-Road Driving with Your
Four
-Wheel-Drive Vehicle
This off-road guide is for vehicles that have
four
-wheel drive.
Also, see ªAnti
-Lock Brakesº in the Index.
If your vehicle doesn't have four
-wheel drive, you
shouldn't drive off
-road unless you're on a level,
solid surface.
Off
-road driving can be great fun. But it does have
some definite hazards. The greatest of these is the
terrain itself.
ªOff
-roadingº means you've left the great North
American road system behind. Traffic lanes aren't
marked. Curves aren't banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill.
In short, you've gone right back to nature.
Off
-road driving involves some new skills. And that's
why it's very important that you read this guide. You'll
find many driving tips and suggestions. These will help
make your off
-road driving safer and more enjoyable.
Before You Go Off-Roading
There are some things to do before you go out.
For example, be sure to have all necessary maintenance
and service work done. Check to make sure all
underbody shields (if so equipped) are properly
attached. Be sure you read all the information about
your four
-wheel-drive vehicle in this manual. Is there
enough fuel? Is the spare tire fully inflated? Are the
fluid levels up where they should be? What are the local
laws that apply to off
-roading where you'll be driving?
If you don't know, you should check with law
enforcement people in the area. Will you be on
someone's private land? If so, be sure to get the
necessary permission.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.

4-45 Dinghy Towing
When towing your vehicle, turn the ignition off.
To prevent your battery from draining while towing,
remove the Ignition A and the Ignition B fuses from the
engine compartment fuse block. Be sure to reinstall the
fuse when you reach your destination. See ªFuses and
Circuit Breakersº in the Index.
Tw o
-Wheel-Drive Vehicles
Tw o
-wheel-drive vehicles, should not be towed with
all four wheels on the ground. Two
-wheel-drive
transmissions have no provisions for internal lubrication
while being towed. To properly tow these vehicles,
they should be placed on a platform trailer with all
four wheels off the ground.
In rare cases when it's unavoidable that a
two
-wheel-drive vehicle is to be towed with all
four wheels on the ground, the propeller shaft to
axle yoke orientation should be marked and the
propeller shaft removed following the applicable
service manual removal/installation procedure.
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmission fluid level before driving the truck.Four
-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Firmly set the parking brake.
2. Shift the transmission to PARK (P).
3. Securely attach the vehicle being towed to the
tow vehicle.

4-46
4. Shift the transfer case to NEUTRAL (N).
See ªFour
-Wheel Driveº in the Index for the
proper procedure to select the NEUTRAL position
for your vehicle.
5. Release the parking brake only after the vehicle
being towed is firmly attached to the towing vehicle.
6. Turn the ignition off. This unlocks the steering
column and reduces battery drain as long as the
Ignition A and Ignition B fuses are removed.
Unlocking the steering column will allow the
proper movement of the front wheels and tires
during towing.
CAUTION:
Shifting a four-wheel-drive vehicle's transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P). You or
others could be injured. Make sure the parking
brake is firmly set before you shift the transfer
case to NEUTRAL.
Dolly Towing
Your vehicle was not designed to be dolly towed. If you
need to tow your vehicle see ªDinghy Towingº earlier in
this section.
CAUTION:
Shifting a four-wheel-drive vehicle's transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P).
You or others could be injured. Make sure the
parking brake is firmly set before you shift the
transfer case into NEUTRAL.

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CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won't move, even
when you're on fairly level ground, use the steps
that follow.
Always put the shift lever fully in PARK (P) with
the parking brake firmly set.
If the transfer case on four-wheel drive vehicles is
in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear
-- not
in NEUTRAL. See ªFour
-Wheel Drive
(Automatic Transfer Case)º in the Index.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

start your engine,

shift into a gear, and

release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake system. Each of these is covered in this
manual, and the Index will help you find them quickly.
If you're trailering, it's a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.

5-4
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
If you have a four
-wheel-drive vehicle, be sure the
transfer case is not in NEUTRAL (N).
NOTICE:
If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets (if equipped). Turn
off the radio and all lamps that aren't needed. This
will avoid sparks and help to save both batteries.
And it could save your radio!
4. Open both hoods and locate the batteries. Find the
positive (+) and negative (
-) terminals on each
battery. Your vehicle has a remote negative (
-) jump
starting terminal. You should always use this remote
terminal instead of the terminal on the battery. The
remote negative (
-) terminal is located on the front
engine lift bracket and is marked ªGND.º See
ªEngine Compartment Overviewº in the Index for
more information on location.