2008 GMC ACADIA ECU

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.
The passenger sensing system is designed to enable
(may inate) the right front passenger’s frontal
airbag and seat-mounted side impact airbag anytime the
system senses that a person of adult size is sitting
properly in the right front passenger’s seat. When the
passenger sensing system has allowed the airbags to be
enabled, the on indicator will light and stay lit to
remind you that the airbags are active.
For some children who have outgrown child restraints
and for very small adults, the passenger sensing system
may or may not turn off the right front passenger’s frontal
airbag and seat-mounted side impact airbag, depending
upon the person’s seating posture and body build.
Everyone in your vehicle who has outgrown child
restraints should wear a safety belt properly — whether
or not there is an airbag for that person.If a person of adult-size is sitting in the right front
passenger’s seat, but the off indicator is lit, it could be
because that person is not sitting properly in the seat. If
this happens, turn the vehicle off, remove any additional
material from the seat, such as blankets, cushions,
seat covers, seat heaters or seat massagers and ask
the person to place the seatback in the fully upright
position, then sit upright in the seat, centered on the seat
cushion, with the person’s legs comfortably extended.
Restart the vehicle and have the person remain in
this position for two to three minutes. This will allow the
system to detect that person and then enable the
right front passenger’s frontal airbag and seat-mounted
side impact airbag.
1-73

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, front sensors, side impact
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 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 1-70.
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 5-66
for additional important information.
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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......................................2-7
Doors and Locks............................................2-10
Door Locks..................................................2-10
Power Door Locks........................................2-11
Delayed Locking...........................................2-11
Programmable Automatic Door Locks..............2-11
Rear Door Security Locks..............................2-11
Lockout Protection........................................2-12
Liftgate........................................................2-13
Power Liftgate..............................................2-14
Windows........................................................2-18
Power Windows............................................2-19
Sun Visors...................................................2-21
Theft-Deterrent Systems..................................2-21
Content Theft-Deterrent.................................2-21
PASS-Key
®III+............................................2-23
PASS-Key®III+ Operation..............................2-23
Starting and Operating Your Vehicle................2-25
New Vehicle Break-In....................................2-25
Ignition Positions..........................................2-26Retained Accessory Power (RAP)...................2-27
Starting the Engine.......................................2-27
Engine Coolant Heater..................................2-29
Automatic Transmission Operation...................2-30
Tow/Haul Mode............................................2-34
Parking Brake..............................................2-35
Shifting Into PARK (P)...................................2-36
Shifting Out of PARK (P)...............................2-37
Parking Over Things That Burn.......................2-38
Engine Exhaust............................................2-38
Running the Engine While Parked...................2-39
Mirrors...........................................................2-40
Manual Rearview Mirror with OnStar
®..............2-40
Automatic Dimming Rearview Mirror with
OnStar
®and Compass...............................2-40
Outside Power Mirrors...................................2-42
Outside Power Foldaway Mirrors.....................2-43
Outside Convex Mirror...................................2-44
Outside Heated Mirrors..................................2-44
Object Detection Systems...............................2-45
Ultrasonic Rear Parking
Assist (URPA)...........................................2-45
Rear Vision Camera......................................2-47
OnStar
®System.............................................2-47
Section 2 Features and Controls
2-1

Power Door Locks
The power door lock switches are located on the front
doors.
K(Unlock):Press to unlock the doors.
Q(Lock):Press to lock the doors.
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 3-75.
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 3-75for 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.
2-11

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.
When you want to open a rear door when the security
lock is on, do the following:
1. Unlock the door using the remote keyless entry
transmitter, if the vehicle has one, the power
door lock switch, or the rear door manual lock.
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. Lock Label shown
2-12

Sun Visors
Pull the sun visor down to block glare. Detach the sun
visor from the center mount and slide it along the
rod from side-to-side to cover the driver or passenger
side of the front window. Swing the sun visor to the side
to cover the side window. It can be moved along the
rod from side-to-side in this position also.
Lighted Visor Vanity Mirror
Your vehicle has lighted visor vanity mirrors on both the
driver’s and passenger’s sun visors. Pull the sun
visor down and lift the mirror cover to turn the lamps on.
Theft-Deterrent Systems
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make it
impossible to steal.
Content Theft-Deterrent
Your vehicle may have a content theft-deterrent alarm
system.To activate the theft-deterrent system, do one of the
following:
Press the lock button on the Remote Keyless Entry
(RKE) transmitter when any door is open.
The security light should come on and ash. When
the door is closed, the security light will stop
ashing and stay on solid and then go off after
approximately 30 seconds. The content theft
deterrent alarm is not armed until the security light
goes off.
If the delayed locking feature is active, the alarm
will not be activated until all doors are closed
and the security light goes off.
Press the lock button on the RKE transmitter when
the driver door is closed.
The security light will come on solid for
approximately 30 seconds and then go off. The
content theft deterrent alarm is not armed until the
security light goes off.
2-21

If a locked door is opened without using the key in the
driver’s door key cylinder or 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.
Here is how 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 a door with the RKE transmitter.
Unlocking a door any other way will set off the alarm
if the system has been armed.If you set off the alarm by accident, turn off the alarm by
pressing unlock on the RKE transmitter or by placing
the key in the ignition and turning it to START.
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
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.
If the alarm does not sound when it should, but the
vehicle’s 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 5-100.
If the alarm does not sound or the vehicle’s headlamps
do not ash, see your dealer/retailer for service.
2-22

PASS-Key®III+
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 your vehicle.
PASS-Key®III+ 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 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.
2-23