2008 CHEVROLET SUBURBAN ECU

The passenger sensing system is designed to turn off
the right front passenger’s frontal airbag if:
The right front passenger seat is unoccupied.
The system determines that an infant is present in
a rear-facing infant seat.
The system determines that a small child is present
in a child restraint.
The system determines that a small child is present
in a booster seat.
A right front passenger takes his/her weight off of
the seat for a period of time.
The right front passenger seat is occupied by a
smaller person, such as a child who has outgrown
child restraints.
Or, if there is a critical problem with the airbag
system or the passenger sensing system.
When the passenger sensing system has turned off the
right front passenger’s frontal airbag, the off indicator
will light and stay lit to remind you that the airbag is off.
SeePassenger Airbag Status Indicator on page 3-38.If a child restraint has been installed and the on
indicator is lit, turn the vehicle off. Remove the child
restraint from the vehicle and reinstall the child restraint
following the child restraint manufacturer’s directions
and refer toSecuring a Child Restraint in the Right
Front Seat Position on page 1-72.
If, after reinstalling the child restraint and restarting
the vehicle, the on indicator is still lit, check to make
sure that the vehicle’s seatback is not pressing the
child restraint into the seat cushion. If this happens,
slightly recline the vehicle’s seatback and adjust the
seat cushion if possible. Also make sure the child
restraint is not trapped under the vehicle head restraint.
If this happens, adjust the head restraint. SeeHead
Restraints on page 1-10.
Remove any additional material from the seat such
as blankets, cushions, seat covers, seat heaters,
or seat massagers before reinstalling or securing
the child restraint.
If the on indicator is still lit, secure the child in the
child restraint in a rear seat position in the vehicle,
and check with your dealer/retailer.
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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 1-85.
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 5-84
for additional important information.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.
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Keys...............................................................2-3
Remote Keyless Entry (RKE) System................2-4
Remote Keyless Entry (RKE) System
Operation...................................................2-5
Remote Vehicle Start......................................2-8
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-10
Delayed Locking...........................................2-11
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-12
Liftgate/Liftglass............................................2-12
Power Liftgate..............................................2-14
Power Running Boards..................................2-17
Windows........................................................2-18
Power Windows............................................2-19
Sun Visors...................................................2-20
Theft-Deterrent Systems..................................2-20
Content Theft-Deterrent.................................2-21
PASS-Key
®III+ Electronic Immobilizer.............2-22
PASS-Key®III+ Electronic Immobilizer
Operation.................................................2-23Starting and Operating Your Vehicle................2-24
New Vehicle Break-In....................................2-24
Ignition Positions..........................................2-25
Retained Accessory Power (RAP)...................2-26
Starting the Engine.......................................2-26
Adjustable Throttle and Brake Pedal................2-28
Engine Coolant Heater..................................2-28
Active Fuel Management™.............................2-29
Automatic Transmission Operation...................2-30
Tow/Haul Mode............................................2-36
Four-Wheel Drive..........................................2-36
Parking Brake..............................................2-42
Shifting Into Park..........................................2-43
Shifting Out of Park......................................2-45
Parking Over Things That Burn.......................2-45
Engine Exhaust............................................2-46
Running the Vehicle While Parked..................2-46
Mirrors...........................................................2-47
Automatic Dimming Rearview Mirror with
OnStar
®, Compass and Temperature
Display....................................................2-47
Automatic Dimming Rearview Mirror with
Compass and Temperature Display..............2-49
Section 2 Features and Controls
2-1

Delayed Locking
When locking the doors with the power lock switch and
a door or the liftgate is open, the doors will lock ve
seconds after the last door is closed. You will hear
three chimes to signal that the delayed locking feature
is in use.
Pressing the power lock switch twice or the lock button
on the RKE transmitter twice will override the delayed
locking feature and immediately lock all the doors.
This feature will not operate if the key is in the ignition.
You can program this feature using the Driver
Information Center (DIC). See DELAY DOOR LOCK
underDIC Vehicle Customization (With DIC Buttons)
on page 3-67.
Programmable Automatic Door
Locks
Vehicles with an automatic lock/unlock feature enable
you to program the vehicle’s power door locks. You can
program this feature through the Driver Information
Center (DIC). SeeDIC Vehicle Customization (With DIC
Buttons) on page 3-67for more information on DIC
programming.
Rear Door Security Locks
Your vehicle has rear door security locks. These
prevent passengers from opening the rear doors
from the inside.
The rear door security
locks are located on the
inside edge of each
rear door.
The rear doors must be open to access them.
The label showing lock and unlock positions is
located near the lock.
To set the locks, do the following:
1. Insert the key into the security lock slot and turn it
so the slot is in the horizontal position.
2. Close the door.
2-11

When you want to open a rear door when the security
lock is on, do the following:
1. Unlock the door by lifting the rear door manual lock,
using the power door lock switch, or the Remote
Keyless Entry (RKE) transmitter, if the vehicle
has one.
2. Open the door from the outside.
To cancel the rear door security lock, do the following:
1. Unlock the door and open it from the outside.
2. Insert the key into the security lock slot and turn it
so the slot is in the vertical position.
Lockout Protection
This feature protects you from locking the key in the
vehicle when the key is in the ignition and a front door
is open.
If the driver’s side power door lock switch is pressed
when the driver’s door is open and the key is in
the ignition, all of the doors will lock and then the driver’s
door will unlock.
If the passenger’s side power door lock switch is
pressed when the front passenger’s door is open and
the key is in the ignition, all of the doors will lock
and then the front passenger’s door will unlock.
Liftgate/Liftglass
{CAUTION:
It can be dangerous to drive with the liftglass
or liftgate open because carbon monoxide
(CO) gas can come into your vehicle. You
cannot see or smell CO. It can cause
unconsciousness and even death.
If you must drive with the liftglass or liftgate
open, or if electrical wiring or other cable
connections must pass through the seal
between the body and the liftglass or liftgate:
Make sure all other windows are shut.
Turn the fan on your heating or cooling
system to its highest speed with the
recirculation mode off. That will force
outside air into your vehicle. SeeClimate
Control System on page 3-22orDual
Automatic Climate Control System on
page 3-24.
CAUTION: (Continued)
2-12

Content Theft-Deterrent
Your vehicle may have a content theft-deterrent alarm
system.
This is the security light.
To arm the theft-deterrent system:
1. Open the door.
2. Lock the door with the Remote Keyless Entry (RKE)
transmitter or the power door lock switch. The
security light will come on to inform the driver the
system is arming. If a door is open when the doors
are locked, the security light will ash.
If the delayed locking feature is turned on, the
theft-deterrent system will not start the arming
process until the last door is closed and the delay
timer has expired. SeeDelayed Locking on
page 2-11.3. Close all doors. The security light should go off
after about 30 seconds. The alarm is not armed
until the security light goes off.
If a locked door is opened without using the RKE
transmitter, a ten second pre-alarm will occur. The horn
will chirp and the lights will ash. If the key is not
placed in the ignition and turned to START or the door
is not unlocked by pressing the unlock button on the
RKE transmitter during the ten second pre-alarm,
the alarm will go off. Your vehicle’s headlamps will ash
and the horn will sound for about two minutes, then
will turn off to save the battery power.
The theft-deterrent system will not activate if the doors
are locked with the vehicle’s key or the manual door lock.
It activates only if you use the power door lock switch with
the door open or the RKE transmitter. You should also
remember that you can start your vehicle with the correct
ignition key if the alarm has been set off.
To avoid setting off the alarm by accident:
If you do not want to activate the theft-deterrent
system, the vehicle should be locked with the
door key after the doors are closed.
Always unlock the doors with the RKE transmitter.
Unlocking a door any other way will set off the
alarm if it is armed.
2-21

If you set off the alarm by accident, press unlock on the
RKE transmitter or place the key in the ignition and
turn it to START to turn off the alarm. The alarm will not
stop if you try to unlock a door any other way.
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.
While 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 5-119.
If the alarm does not sound or the headlamps do not
ash, the vehicle should be serviced by your
dealer/retailer.
PASS-Key®III+ Electronic
Immobilizer
The PASS-Key III+ 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 harmful interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation.
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.
PASS-Key III+ uses a radio frequency transponder in
the key that matches a decoder in the vehicle.
2-22

PASS-Key®III+ Electronic
Immobilizer Operation
Your vehicle has PASS-Key®III+ (Personalized
Automotive Security System) theft-deterrent system.
PASS-Key
®III+ is a passive theft-deterrent system.
The system is automatically armed when the key
is removed from the ignition.
The system is automatically disarmed when the key is
turned to ON/RUN, ACC/ACCESSORY or START
from the LOCK/OFF position.
You do not have to manually arm or disarm the system.
The security light will come on if there is a problem
with arming or disarming the theft-deterrent system.
When the PASS-Key
®III+ system senses that someone
is using the wrong key, it prevents the vehicle from
starting. Anyone using a trial-and-error method to start
the vehicle will be discouraged because of the high
number of electrical key codes.
If the engine does not start and the security light on the
instrument panel cluster comes on when trying to
start the vehicle, there may be a problem with your
theft-deterrent system. Turn the ignition off and try again.If the engine still does not start, and the key appears to
be undamaged, try another ignition key. At this time,
you may also want to check the fuse, seeFuses
and Circuit Breakers on page 5-119. If the engine still
does not start with the other key, your vehicle needs
service. If your vehicle does start, the rst key may be
faulty. See your dealer/retailer who can service the
PASS-Key
®III+ to have a new key made. In an
emergency, contact Roadside Assistance.
It is possible for the PASS-Key
®III+ decoder to learn
the transponder value of a new or replacement key. Up
to 10 keys may be programmed for the vehicle. The
following procedure is for programming additional keys
only. If all the currently programmed keys are lost or
do not operate, you must see your dealer/retailer
or a locksmith who can service PASS-Key
®III+ to have
keys made and programmed to the system.
See your dealer/retailer or a locksmith who can service
PASS-Key
®III+ to get a new key blank that is cut
exactly as the ignition key that operates the system.
2-23