2008 GMC ENVOY service

Seats and Restraint Systems........................... 1-1
Front Seats
............................................... 1-2
Rear Seats
..............................................1-11
Safety Belts
.............................................1-13
Child Restraints
.......................................1-32
Airbag System
.........................................1-53
Restraint System Check
............................1-68
Features and Controls..................................... 2-1
Keys
........................................................ 2-3
Doors and Locks
....................................... 2-7
Windows
.................................................2-13
Theft-Deterrent Systems
............................2-16
Starting and Operating Your Vehicle
...........2-20
Mirrors
....................................................2-39
OnStar
®System
......................................2-48
Universal Home Remote System
................2-52
Storage Areas
.........................................2-57
Sunroof
..................................................2-60
Instrument Panel............................................. 3-1
Instrument Panel Overview
.......................... 3-4
Climate Controls
......................................3-21
Warning Lights, Gages, and Indicators
........3-30
Driver Information Center (DIC)
..................3-49
Audio System(s)
.......................................3-65Driving Your Vehicle....................................... 4-1
Your Driving, the Road, and Your Vehicle
..... 4-2
Towing
...................................................4-40
Service and Appearance Care.......................... 5-1
Service
..................................................... 5-3
Fuel
......................................................... 5-5
Checking Things Under the Hood
...............5-10
Rear Axle
...............................................5-46
Four-Wheel Drive
.....................................5-47
Front Axle
...............................................5-48
Headlamp Aiming
.....................................5-49
Bulb Replacement
....................................5-49
Windshield Wiper Blade Replacement
.........5-54
Tires
......................................................5-57
Appearance Care
...................................5-100
Vehicle Identication
...............................5-108
Electrical System
....................................5-109
Capacities and Specications
...................5-120
Maintenance Schedule..................................... 6-1
Maintenance Schedule
................................ 6-2
Customer Assistance Information.................... 7-1
Customer Assistance and Information
........... 7-2
Reporting Safety Defects
...........................7-15
Vehicle Data Recording and Privacy
...........7-18
Index................................................................ 1
2008 GMC Envoy and Envoy Denali Owner ManualM

In many crashes severe enough to inate the airbag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur
from the right front passenger airbag.
Airbags are designed to inate only once. After an
airbag inates, you will need some new parts for the
airbag system. If you do not get them, the airbag
system will not be there to help protect you in another
crash. A new system will include airbag modules and
possibly other parts. The service manual for your
vehicle covers the need to replace other parts.
Your vehicle has a crash sensing and diagnostic
module which records information after a crash.
SeeVehicle Data Recording and Privacy on
page 7-18andEvent Data Recorders on page 7-18.
Let only qualied technicians work on the airbag
systems. Improper service can mean that an airbag
system will not work properly. See your dealer/
retailer for service.
Passenger Sensing System
Your vehicle has a passenger sensing system for
the right front passenger’s position. The passenger
airbag status indicator will be visible in the rearview
mirror when you start your vehicle.
The words ON and OFF, or the symbol for on and off, will
be visible during the system check. When the system
check is complete, either the word ON or the word OFF,
or the symbol for on or the symbol for off, will be visible.
SeePassenger Airbag Status Indicator on page 3-34. United States
Canada
1-61

{CAUTION:
If the airbag readiness light in the instrument
panel cluster ever comes on and stays on, it
means that something may be wrong with the
airbag system. If this ever happens, have the
vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger’s seat may not have the protection
of the airbag(s). SeeAirbag Readiness Light
on page 3-33for more on this, including
important safety information.A thick layer of additional material, such as a blanket or
cushion, or aftermarket equipment such as seat covers,
seat heaters, and seat massagers can affect how well
the passenger sensing system operates. We recommend
that you not use seat covers or other aftermarket
equipment other than any that GM has approved for
your specic vehicle. SeeAdding Equipment to Your
Airbag-Equipped Vehicle on page 1-66for more
information about modications that can affect
how the system operates.
{CAUTION:
Stowing of articles under the passenger’s seat
or between the passenger’s seat cushion
and seatback may interfere with the proper
operation of the passenger sensing system.
1-65

Servicing Your Airbag-Equipped
Vehicle
Airbags affect how your vehicle should be serviced.
There are parts of the airbag system in several places
around your vehicle. Your dealer/retailer and the service
manual have information about servicing your vehicle
and the airbag system. To purchase a service manual,
seeService Publications Ordering Information on
page 7-16.
{CAUTION:
For up to 10 seconds after the ignition is
turned off and the battery is disconnected, an
airbag can still inate during improper service.
You can be injured if you are close to an airbag
when it inates. Avoid yellow connectors. They
are probably part of the airbag system. Be sure
to follow proper service procedures, and make
sure the person performing work for you is
qualied to do so.
Adding Equipment to Your
Airbag-Equipped Vehicle
Q:Is there anything I might add to or change
about the vehicle that could keep the airbags
from working properly?
A:Yes. If you add things that change your vehicle’s
frame, bumper system, height, front end or side
sheet metal, they may keep the airbag system from
working properly. Changing or moving any parts
of the front seats, safety belts, the airbag sensing
and diagnostic module, steering wheel, instrument
panel, roof-rail airbag modules, ceiling headliner
or pillar garnish trim, rearview mirror, front sensors,
rollover sensor module, or airbag wiring can
affect the operation of the airbag system.
In addition, your vehicle has a passenger sensing
system for the right front passenger’s position,
which includes sensors that are part of the
passenger’s seat. The passenger sensing
system may not operate properly if the original
seat trim is replaced with non-GM covers,
upholstery or trim, or with GM covers, upholstery
or trim designed for a different vehicle.
1-66

Any object, such as an aftermarket seat heater or a
comfort enhancing pad or device, installed under or
on top of the seat fabric, could also interfere with
the operation of the passenger sensing system.
This could either prevent proper deployment of the
passenger airbag(s) or prevent the passenger
sensing system from properly turning off the
passenger airbag(s). SeePassenger Sensing
System on page 1-61.
If you have any questions about this, you should
contact Customer Assistance before you modify
your vehicle. The phone numbers and addresses
for Customer Assistance are in Step Two of
the Customer Satisfaction Procedure in this manual.
SeeCustomer Satisfaction Procedure on page 7-2.
If your vehicle has rollover roof-rail airbags, see
Different Size Tires and Wheels on page 5-76
for additional important information.Q:Because I have a disability, I have to get my
vehicle modied. How can I nd out whether
this will affect my airbag system?
A:If you have questions, call Customer Assistance.
The phone numbers and addresses for Customer
Assistance are in Step Two of the Customer
Satisfaction Procedure in this manual. See
Customer Satisfaction Procedure on page 7-2.
In addition, your dealer/retailer and the service manual
have information about the location of the airbag sensors,
sensing and diagnostic module and airbag wiring.
1-67

Restraint System Check
Checking the Restraint Systems
Safety Belts
Now and then, make sure the safety belt reminder light
and all your belts, buckles, latch plates, retractors
and anchorages are working properly.
Look for any other loose or damaged safety belt system
parts. If you see anything that might keep a safety belt
system from doing its job, have it repaired. Torn or frayed
safety belts may not protect you in a crash. They can rip
apart under impact forces. If a belt is torn or frayed, get a
new one right away.
Make sure the safety belt reminder light is working.
SeeSafety Belt Reminders on page 3-32for more
information.
Keep safety belts clean and dry. SeeCare of Safety
Belts on page 5-103.
Airbags
The airbag system does not need regularly scheduled
maintenance or replacement. Make sure the airbag
readiness light is working. SeeAirbag Readiness
Light on page 3-33for more information.
Notice:If an airbag covering is damaged, opened,
or broken, the airbag may not work properly.
Do not open or break the airbag coverings. If there
are any opened or broken airbag covers, have
the airbag covering and/or airbag module replaced.
For the location of the airbag modules, seeWhat
Makes an Airbag Inflate? on page 1-59.
See your dealer/retailer for service.
1-68

The key code number tells your dealer/retailer or a
qualied locksmith how to make extra keys. Keep this
number in a safe place. If you lose your keys, you will be
able to have new ones made easily using this number.
Your selling dealer/retailer should also have this
number.
Notice:If you ever lock your keys in your vehicle,
you may have to damage the vehicle to get in.
Be sure you have spare keys.
If you ever get locked out of your vehicle, call the
Roadside Assistance Center. SeeRoadside Assistance
Program on page 7-8.
Remote Keyless Entry (RKE)
System
Your Remote Keyless Entry (RKE) system operates on
a radio frequency subject to Federal Communications
Commission (FCC) Rules and with Industry Canada.
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.This device complies with RSS-210 of Industry Canada.
Operation is subject to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
Changes or modications 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 operating range.
This is normal for any RKE 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 is
necessary. See “Battery Replacement” later in
this section.
If you are still having trouble, see your dealer/retailer
or a qualied technician for service.
2-4

Testing the Alarm
To test the alarm:
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 RKE 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 will
not work.
If the alarm does not sound when it should but the
headlamps ash, check to see if the horn works.
The horn fuse may be blown. To replace the fuse,
seeFuses and Circuit Breakers on page 5-110.
If the alarm does not sound or the headlamps do
not ash, the vehicle should be serviced by your
dealer/retailer.
Passlock®(U. S. Only)
Your vehicle has the Passlock®theft-deterrent system.
Passlock®is a passive theft-deterrent system that
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 has been tampered with, the fuel system is
disabled and the vehicle will not start.
During normal operation, the security light will turn off
about ve seconds after the key is turned to ON/RUN.
If the engine stalls and the security light ashes,
wait about 10 minutes until the light stops ashing 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/retailer.
Your vehicle is not protected by Passlock
®at this time.
You may also want to check the fuse. SeeFuses and
Circuit Breakers on page 5-110. See your dealer/retailer
for service.
In an emergency, call the Roadside Assistance Center.
SeeRoadside Assistance Program on page 7-8.
Do not leave the key or device that disarms or
deactivates the theft deterrent system in the vehicle.
2-17