2002 GMC ENVOY service

1-29
In many crashes severe enough to inflate an air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from
the right front passenger air bag.

Air bags are designed to inflate only once. After an
air bag inflates, you'll need some new parts for your
air bag system. If you don't get them, the air bag
system won't be there to help protect you in another
crash. A new system will include air bag modules
and possibly other parts. The service manual for
your vehicle covers the need to replace other parts.

Your vehicle is equipped with an electronic frontal
sensor, which helps the sensing system distinguish
between a moderate frontal impact and a more
severe frontal impact. Your vehicle is also equipped
with a crash sensing and diagnostic module, which
records information about the frontal air bag system.
The module records information about the readiness
of the system, when the system commands air bag
inflation and driver's safety belt usage at deployment.
The module also records speed, engine rpm, brake
and throttle data.

Let only qualified technicians work on your air
bag systems. Improper service can mean that an
air bag system won't work properly. See your dealer
for service.
NOTICE:
If you damage the covering for the driver's
or the right front passenger's air bag, or the
air bag covering on the driver's and right front
passenger's seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right
front passenger's air bag, or both the air bag
module and seatback for the driver's and right
front passenger's side impact air bag. Do not
open or break the air bag coverings.

1-30 Servicing Your Air Bag-Equipped Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag systems in several places
around your vehicle. Your dealer and the service manual
have information about servicing your vehicle and the
air bag systems. To purchase a service manual, see
ªService and Owner Publicationsº in the Index.
CAUTION:
For up to 10 seconds after the ignition key is
turned off and the battery is disconnected, an air
bag can still inflate during improper service. You
can be injured if you are close to an air bag when
it inflates. Avoid yellow connectors. They are
probably part of the air bag systems. Be sure to
follow proper service procedures, and make sure
the person performing work for you is qualified
to do so.
The air bag systems do not need regular maintenance.
Rear Seat Passengers
It's very important for rear seat passengers to buckle up!
Accident statistics show that unbelted people in the rear
seat are hurt more often in crashes than those who are
wearing safety belts.
Rear passengers who aren't safety belted can be thrown
out of the vehicle in a crash. And they can strike others
in the vehicle who are wearing safety belts.
Rear Seat Passenger Positions

2-11
Changes or modifications to this system by other than an
authorized service facility could void authorization to
use this equipment.
At times you may notice a decrease in range. This is
normal for any remote keyless entry system. If the
transmitter does not work or if you have to stand closer
to your vehicle for the transmitter to work, try this:

Check the distance. You may be too far from your
vehicle. You may need to stand closer during rainy
or snowy weather.

Check the location. Other vehicles or objects may be
blocking the signal. Take a few steps to the left or
right, hold the transmitter higher, and try again.

Check to determine if battery replacement or
resynchronization is necessary. See the instructions
that follow.

If you're still having trouble, see your dealer or a
qualified technician for service.Operation
(Unlock): When you
press unlock, the driver's
door will unlock
automatically, the parking
lamps may flash and the
interior lights will go on.
You can program different feedback settings through the
Driver Information Center (DIC). For more information
see ªDriver Information Center (DIC)º in the Index.
(Lock): Press lock to lock all the doors. Press lock
again within three seconds and the horn will chirp.
(Panic): When the button with the horn symbol
on the key transmitter is pressed, the horn will sound
and the headlamps and taillamps will flash for up to
30 seconds. This can be turned off by pressing the horn
button again, or by waiting for 30 seconds, or by starting
the vehicle.

2-16
If a locked door is opened without the key or the remote
keyless entry transmitter, the alarm will go off. The
headlamps and parking lamps will flash for two minutes,
and the horn will sound for 30 seconds, then will turn
off to save the battery power.
Remember, the theft
-deterrent system won't activate if
you lock the doors with a key or use the manual door
lock. It activates only if you use a power door lock
switch with the door open, or with the remote keyless
entry transmitter. You should also remember that you
can start your vehicle with the correct ignition key if the
alarm has been set off.
Here's how to avoid setting off the alarm by accident:

If you don't want to activate the theft
-deterrent
system, the vehicle should be locked with the door
key after the doors are closed.

Always unlock a door with a key, or use the remote
keyless entry transmitter. Unlocking a door any other
way will set off the alarm.
If you set off the alarm by accident, unlock any door
with the key. You can also turn off the alarm by
pressing unlock on the remote keyless entry
transmitter. The alarm won't stop if you try to unlock
a door any other way.
Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, lower the driver's window
and open the driver's door.
2. Activate the system by locking the doors with the
power door lock switch while the door is open, or
with the remote keyless entry transmitter.
3. Get out of the vehicle, close the door and wait for the
SECURITY light to go out.
4. Then reach in through the window, unlock the door
with the manual door lock and open the door. This
should set off the alarm.
When the alarm is set the power door unlock switch is
not operational.
If the alarm does not sound when it should but the
headlamps flash, check to see if the horn works. The
horn fuse may be blown. To replace the fuse, see ªFuses
and Circuit Breakersº in the Index.
If the alarm does not sound or the headlamps do not
flash, the vehicle should be serviced by your dealer.

2-17
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, the fuel system is disabled
and the vehicle will not start.
During normal operation, the SECURITY light will
turn 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 light 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.

2-19
A (Lock): This position locks the ignition and
transmission. It's a theft
-deterrent feature. You will
only be able to remove the key when the ignition is
turned to LOCK.
NOTICE:
If your key seems stuck in LOCK and you can't
turn it, be sure you are using the correct key; if
so, is it all the way in? Turn the key only with
your hand. Using a tool to force it could break
the key or the ignition switch. If none of this
works, then your vehicle needs service.
B (Accessory): This position lets you use things like the
radio and the windshield wipers when the engine is off.
NOTICE:
Don't operate accessories in the ACCESSORY
position for long periods of time. Prolonged
operation of accessories in the ACCESSORY
position could drain the battery and prevent you
from starting your vehicle.
C (Run): This is the position for driving.
D (Start): This position starts the engine.
Retained Accessory Power (RAP)
Your vehicle is equipped with a Retained Accessory
Power (RAP) feature which will allow certain features
of your vehicle to continue to work up to 20 minutes
after the ignition key is turned to LOCK.
Your radio, power windows, sunroof (option) and
overhead console will work when the ignition key is in
RUN or ACCESSORY. Once the key is turned from
RUN to LOCK, these features will continue to work for
up to 20 minutes or until a door is opened.

2-28
4HI: Use 4HI when you need extra traction, such as
on snowy or icy roads or in most off
-road situations.
This setting also engages your front axle to help drive
your vehicle.
4LO: This setting also engages your front axle and
delivers extra torque. You may never need 4LO. It sends
maximum power to all four wheels. You might choose
4LO if you are driving off
-road in deep sand, deep mud,
and climbing or descending steep hills.
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 in the Index
for more information.
An indicator light in the knob will show you which
position the transfer case is 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 on the instrument panel
cluster stays on, you should take your vehicle to your
dealer for service. See ªService 4WDº in the Index for
further information.

2-51
Battery Run-Down Protection
This feature shuts off the dome, courtesy, vanity,
reading, glove box and underhood lamps if they are left
on for more than 20 minutes when the ignition is off.
This will keep your battery from running down.
If the battery run
-down protection shuts off the interior
lamps, it may be necessary to do one of the following to
return to normal operation:

Shut off all lamps and close all doors, or

turn the ignition key to RUN.
This feature will also turn off the parking lamps and
headlamps under most circumstances, if they are left on.
If you would like to turn them back on, turn the exterior
lamps knob on.
Mirrors
Adjust all the mirrors so you can see clearly when you
are sitting in a comfortable driving position.
Electrochromic Day/Night Rearview Mirror
with Compass and OnStar (If Equipped)
Your vehicle has an automatic-dimming rearview mirror
with a compass and the OnStar system.
This is the on/off button.
There are three buttons for the OnStar system. See your
dealer for more information on the system and how to
subscribe to OnStar. See ªOnStar
 Systemº in the Index
for more information about the services OnStar provides.