ignition GMC ENVOY 2002 Repair Manual

3-54 Tips and Troubleshooting Chart
ProblemRecommended Action
No power.The ignition might be on.
The parental control button
might have been pressed.
(The power LED will flash.)
Disc will
not play.The Input/Title on the remote
might be set for auxiliary.
The disc is upside down or
is not compatible.
No sound.The volume on the headphones
could be too low. Adjust it on
the front panel or the remote.
The picture is
distorted during
fast forward or
fast reverse.This is normal for this operation.
ProblemRecommended Action
The picture
does not fill
the screen.
There are black
borders on the
top and bottom
or on both sides
or it looks
stretched out.Quickly press and release the
SIZE/ANGLE button on the
remote. This will fill the screen.
If the screen looks stretched
out, press and release the
SIZE/ANGLE button again.
If there are borders on the top
and bottom, the movie may have
been made that way for a standard
screen. Pressing the SIZE/ANGLE
button should fill the sides.
I ejected the disc
and tried to take
it out, but it was
pulled back into
the slot.Eject the disc again.

3-63 Diversity Antenna System
Your AM FM antennas are located in the rear side
windows. Be sure that the inside surfaces of the rear side
windows are not scratched and that the lines on the glass
are not damaged. If the inside surfaces are damaged,
they could interfere with radio reception.
NOTICE:
Do not try to clear frost or other material from
the inside of the rear side windows with a razor
blade or anything else that is sharp. This may
affect your radio's ability to pick up stations
clearly. The repairs wouldn't be covered by
your warranty.
If you choose to add an aftermarket cellular telephone
to your vehicle, and the antenna needs to be attached to
the glass, be sure that you do not damage the grid lines
for the AM FM antennas or place the cellular telephone
antenna over the grid lines.
Chime Level Adjustment
The volume level of the vehicle's chimes can be
controlled by the radio. To change the volume level,
press and hold pushbutton 6 with the ignition on
and the radio power off. The chime volume level will
change from the normal level to loud, and LOUD will
be displayed on the radio. To change back to the default
or normal setting, press and hold pushbutton 6 again.
The chime level will change from the loud level to
normal, and NORMAL will be displayed.

4-10
The TRAC OFF light on the button will come on under
the following conditions:

The Traction Assist System is turned off, either by
pressing the TAS on/off button or turning off the
automatic engagement feature of the TAS.

The transmission is in FIRST (1); TAS will not
operate in this gear. This is normal.

The vehicle is driven on an extremely rough road.
When the vehicle leaves the rough surface, slows
down or stops, the light will go off and TAS will be
on again. This is normal.

A Traction Assist System, Anti
-Lock Brake System
or engine
-related problem has been detected and the
vehicle needs service.
The Traction Assist System, as delivered from the
factory, will automatically come on whenever you start
your vehicle. To limit wheel spin, especially in slippery
road conditions, you should always leave the system on.
But you can turn the TAS off if you ever need to. You
should turn the TAS off if your vehicle ever gets stuck in
sand, mud or snow and rocking the vehicle is required.
See ªRocking Your Vehicleº in the Index.
To turn the system on
or off press the TAS
on/off button located
near the shift lever.
If you used the button
to turn the system off,
the TRAC OFF light
on the button will
come on and stay on.
You can turn the system back on at any time by pressing
the button again. The TRAC OFF light on the button
should go off.
If desired, you can change the TAS automatic
engagement feature so that the system will not come on
automatically when the engine is started. To do so:
1. Park the vehicle with the ignition off and the
transmission in PARK (P).
2. Turn the ignition to RUN; do not start the engine.

4-11
3. Apply the brake pedal, press the accelerator pedal to
the floor and then press the TAS on/off button and
hold it down for at least six seconds.
4. Release the TAS button and both pedals.
5. Turn off the ignition and wait a few seconds.
The next time you start your vehicle, the TAS will not
automatically come on. You can restore the automatic
feature by using the same procedure. Whether the
TAS is set to come on automatically or not, you can
always turn the system on or off by pressing the TAS
on/off button.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer
but it will take much more effort.
Steering Tips
Driving on Curves
It's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº accidents mentioned
on the news happen on curves. Here's why:Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves. The
traction of the tires against the road surface makes it
possible for the vehicle to change its path when you turn
the front wheels. If there's no traction, inertia will keep
the vehicle going in the same direction. If you've ever
tried to steer a vehicle on wet ice, you'll understand this.
The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle
at which the curve is banked, and your speed.
While you're in a curve, speed is the one factor you
can control.
Suppose you're steering through a sharp curve.
Then you suddenly accelerate. Both control
systems
-- steering and acceleration -- have to do
their work where the tires meet the road. Adding the
sudden acceleration can demand too much of those
places. You can lose control. Refer to ªTraction Assist
Systemº in the Index.
What should you do if this ever happens? Ease up on the
accelerator pedal, steer the vehicle the way you want it
to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds are
based on good weather and road conditions. Under less
favorable conditions you'll want to go slower.

4-29
If the water isn't too deep, then drive through it slowly.
At fast speeds, water splashes on your ignition system
and your vehicle can stall. Stalling can also occur if you
get your tailpipe under water. And, as long as your
tailpipe is under water, you'll never be able to start your
engine. When you go through water, remember that
when your brakes get wet, it may take you longer
to stop.
CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown. If it's
only shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Don't drive
through rushing water.
See ªDriving Through Waterº in the Index for more
information on driving through water.
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.

4-39
If you drive regularly in steep country, or if you're
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. See ªOff
-Road
Drivingº in the Index for information about
driving off
-road.

Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let your engine
assist your brakes on a steep downhill slope.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.

Know how to go uphill. You may want to shift down to
a lower gear. The lower gears help cool your engine and
transmission, and you can climb the hill better.

Stay in your own lane when driving on two
-lane roads
in hills or mountains. Don't swing wide or cut across
the center of the road. Drive at speeds that let you stay
in your own lane.

As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.

You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing or
no
-passing zones, a falling rocks area or winding roads.
Be alert to these and take appropriate action.

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.

4-49 Electronically Controlled Air Suspension
System (If Equipped)
Your vehicle may be equipped with an electronically
controlled air suspension system that automatically
keeps your vehicle level as you load and unload. The
system includes a compressor, two height sensors and
two air springs supporting the rear axle.
The system also has an internal clock to prevent
overheating. If the system overheats, all leveling
function stops until the system cools down. During
this time, the indicator light on the air inflator system
will be flashing.
The ignition has to be on for the system to inflate, in
order to raise the vehicle to the standard ride height after
loading. The system can lower the vehicle to the
standard ride height after unloading with the ignition on
and also for up to 30 minutes after the ignition has been
turned off.
You may hear the compressor operating when you load
your vehicle, and periodically as the system adjusts the
vehicle to the standard ride height.
Load leveling will not function normally with the
inflator hose attached to the inflator outlet. Remove
the inflator hose from the outlet during loading
and unloading.Overload Protection
The air suspension system is equipped with overload
protection. Overload protection is designed to protect
the air suspension system, and it is an indicator to the
driver that the vehicle is overloaded. When the overload
protection mode is on, it will not allow damage to the
air compressor. However, do not overload the vehicle.
See ªLoading Your Vehicleº earlier in this section.
If the suspension remains at a low height, the rear axle
load has exceeded GAWR (Gross Axle Weight Rating).
When the overload protection mode is activated, the
compressor operates for about 30 seconds to one minute
without raising the vehicle depending on the amount
of overload. This will continue each time the ignition
is turned on until the rear axle load is reduced
below GAWR.
Indicator Light
The indicator light on the inflator switch in the rear
passenger compartment also serves as an indicator for
internal system error. If the indicator light is flashing
without the load leveling function or the inflator being
active, turn off the ignition. The next day turn on the
ignition and check the indicator light. The vehicle can
be driven with the light flashing, but if it is you should
have the vehicle serviced as soon as possible.

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.