2008 GMC SIERRA Owner's Manual

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, overhead console, front
sensors, rollover sensor module, or airbag wiring
can affect the operation of the airbag system.
In addition, your vehicle may have 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 seattrim is replaced with non-GM covers, upholstery or
trim, or with GM covers, upholstery or trim
designed for a different vehicle. 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 1-80.
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 5-86
for additional important information.
1-85

Q:What if I added a snow plow? Will it keep the
airbags from working properly?
A:We have designed our airbag systems to work
properly under a wide range of conditions,
including snow plowing with vehicles that have the
optional Snow Plow Prep Package (RPO VYU).
But do not change or defeat the snow plow’s
“tripping mechanism.” If you do, it can damage your
snow plow and your vehicle, and it may cause an
airbag ination.
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.
1-86

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. See
Safety Belt Reminders on page 3-37for more
information.
Keep safety belts clean and dry. SeeCare of Safety
Belts on page 5-115.
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 3-38for 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 1-74. See your
dealer/retailer for service.
1-87

Replacing Restraint System Parts
After a Crash
{CAUTION:
A crash can damage the restraint systems in
your vehicle. A damaged restraint system may
not properly protect the person using it,
resulting in serious injury or even death in a
crash. To help make sure your restraint
systems are working properly after a crash,
have them inspected and any necessary
replacements made as soon as possible.If you have had a crash, do you need new belts or
LATCH system (if equipped) parts?
After a very minor crash, nothing may be necessary.
But the belt assemblies that were used during any crash
may have been stressed or damaged. See your
dealer/retailer to have your safety belt assemblies
inspected or replaced.
If your vehicle has the LATCH system and it was being
used during a crash, you may need new LATCH
system parts.
New parts and repairs may be necessary even if the
belt or LATCH system (if equipped), was not being used
at the time of the crash.
If an airbag inates, you will need to replace airbag
system parts. See the part on the airbag system earlier
in this section.
Have your safety belt pretensioners checked if your
vehicle has been in a crash, if your airbag readiness
light stays on after you start your vehicle, or while you
are driving. SeeAirbag Readiness Light on page 3-38.
1-88

Keys...............................................................2-3
Remote Keyless Entry (RKE) System................2-4
Remote Keyless Entry (RKE) System
Operation...................................................2-5
Remote Vehicle Start......................................2-7
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-10
Delayed Locking...........................................2-10
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-12
Rear Doors..................................................2-13
Tailgate.......................................................2-14
Windows........................................................2-15
Manual Windows..........................................2-16
Power Windows............................................2-16
Power Sliding Rear Window...........................2-17
Sun Visors...................................................2-18
Theft-Deterrent Systems..................................2-18
Content Theft-Deterrent.................................2-18
PASS-Key
®III+............................................2-20
PASS-Key®III+ Operation..............................2-20
Starting and Operating Your Vehicle................2-22
New Vehicle Break-In....................................2-22
Ignition Positions..........................................2-22Retained Accessory Power (RAP)...................2-23
Starting the Engine.......................................2-24
Fast Idle System..........................................2-25
Adjustable Throttle and Brake Pedal................2-26
Engine Coolant Heater..................................2-26
Active Fuel Management™.............................2-27
Automatic Transmission Operation...................2-28
Tow/Haul Mode............................................2-34
Four-Wheel Drive..........................................2-36
Parking Brake..............................................2-49
Shifting Into PARK (P)...................................2-50
Shifting Out of PARK (P)...............................2-52
Parking Over Things That Burn.......................2-53
Engine Exhaust............................................2-53
Running the Engine While Parked...................2-54
Mirrors...........................................................2-55
Manual Rearview Mirror.................................2-55
Automatic Dimming Rearview Mirror with
OnStar
®, Compass and Temperature
Display....................................................2-55
Automatic Dimming Rearview Mirror with
Compass and Temperature Display..............2-57
Outside Manual Mirrors..................................2-58
Outside Trailer-Tow Mirrors............................2-59
Outside Power Mirrors...................................2-59
Outside Power Foldaway Mirrors.....................2-61
Section 2 Features and Controls
2-1

Object Detection Systems...............................2-63
Ultrasonic Rear Parking Assist (URPA)............2-63
OnStar
®System.............................................2-65
Universal Home Remote System......................2-68
Universal Home Remote System.....................2-68
Universal Home Remote System Operation
(With Three Round LED)............................2-69Storage Areas................................................2-74
Glove Box...................................................2-74
Cupholder(s)................................................2-75
Instrument Panel Storage...............................2-75
Center Console Storage.................................2-76
Luggage Carrier...........................................2-76
Rear Seat Armrest........................................2-77
Cargo Management System...........................2-78
Sunroof.........................................................2-79
Section 2 Features and Controls
2-2

Keys
{CAUTION:
Leaving children in a vehicle with the ignition
key is dangerous for many reasons, children
or others could be badly injured or even killed.
They could operate the power windows or
other controls or even make the vehicle move.
The windows will function with the keys in the
ignition and they could be seriously injured or
killed if caught in the path of a closing
window. Do not leave the keys in a vehicle
with children.
The key can be used for the ignition and all door locks.
The key has a bar-coded key tag that the dealer/retailer
or qualied locksmith can use to make new keys.
Store this information in a safe place, not in your vehicle.
See your dealer/retailer if a replacement key or
additional key is needed.
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 are locked out of your vehicle, call the Roadside
Assistance Center. SeeRoadside Assistance Program
on page 7-7.
2-3

Remote Keyless Entry (RKE)
System
If the vehicle has the Remote Keyless Entry (RKE)
system, it 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 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