2008 GMC ACADIA sensor

When Should an Airbag Inate?
Frontal airbags are designed to inate in moderate to
severe frontal or near-frontal crashes to help reduce the
potential for severe injuries mainly to the driver’s or
right front passenger’s head and chest. However, they
are only designed to inate if the impact exceeds a
predetermined deployment threshold. Deployment
thresholds are used to predict how severe a crash is
likely to be in time for the airbags to inate and
help restrain the occupants.
Whether your frontal airbags will or should deploy is not
based on how fast your vehicle is traveling. It depends
largely on what you hit, the direction of the impact,
and how quickly your vehicle slows down.
Frontal airbags may inate at different crash speeds.
For example:
If the vehicle hits a stationary object, the airbags
could inate at a different crash speed than if the
vehicle hits a moving object.
If the vehicle hits an object that deforms, the
airbags could inate at a different crash speed than
if the vehicle hits an object that does not deform.
If the vehicle hits a narrow object (like a pole), the
airbags could inate at a different crash speed
than if the vehicle hits a wide object (like a wall).
If the vehicle goes into an object at an angle, the
airbags could inate at a different crash speed
than if the vehicle goes straight into the object.
Thresholds can also vary with specic vehicle design.
Frontal airbags are not intended to inate during vehicle
rollovers, rear impacts, or in many side impacts.
In addition, your vehicle has dual-stage frontal airbags.
Dual-stage airbags adjust the restraint according to
crash severity. Your vehicle has electronic frontal
sensors, which help the sensing system distinguish
between a moderate frontal impact and a more severe
frontal impact. For moderate frontal impacts, dual-stage
airbags inate at a level less than full deployment.
For more severe frontal impacts, full deployment occurs.
Your vehicle has seat-mounted side impact and
roof-rail airbags. SeeAirbag System on page 1-61.
Seat-mounted side impact and roof-rail airbags
are intended to inate in moderate to severe side
crashes. In addition, these roof-rail airbags are intended
to inate during a rollover or in a severe frontal
impact. Seat-mounted side impact and roof-rail airbags
will inate if the crash severity is above the system’s
designed threshold level. The threshold level can
vary with specic vehicle design.
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The passenger sensing system works with sensors that
are part of the right front passenger’s seat. The
sensors are designed to detect the presence of a
properly-seated occupant and determine if the right front
passenger’s frontal airbag and seat-mounted side
impact airbag should be enabled (may inate) or not.
Accident statistics show that children are safer if
they are restrained in the rear rather than the front seat.
We recommend that children be secured in a rear
seat, including: an infant or a child riding in a rear-facing
child restraint; a child riding in a forward-facing child
seat; an older child riding in a booster seat; and children,
who are large enough, using safety belts.
A label on your sun visor says, “Never put a rear-facing
child seat in the front.” This is because the risk to the
rear-facing child is so great, if the airbag deploys.
{CAUTION:
A child in a rear-facing child restraint can be
seriously injured or killed if the right front
passenger’s airbag inates. This is because
the back of the rear-facing child restraint
would be very close to the inating airbag.
Even though the passenger sensing system is
designed to turn off the right front passenger’s
frontal and seat-mounted side impact airbag (if
equipped) if the system detects a rear-facing
child restraint, no system is fail-safe, and no
one can guarantee that an airbag will not
deploy under some unusual circumstance,
even though it is turned off. We recommend
that rear-facing child restraints be secured in a
rear seat, even if the airbag(s) are off.
If you secure a forward-facing child restraint in
the right front seat, always move the front
passenger seat as far back as it will go. It is
better to secure the child restraint in a rear seat.
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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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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.
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 3-41for more
information.
Keep safety belts clean and dry. SeeCare of Safety
Belts on page 5-92.
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 3-42for 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 1-68. See your
dealer/retailer for service.
1-77

Your vehicle has pinch sensors located on the side
edges of the liftgate. If an object is caught between the
liftgate and the body and presses against this sensor,
the liftgate will reverse direction and open fully.
The liftgate will remain open until it is activated again or
closed manually. Do not force the liftgate open or
closed during a power cycle.
Manual Operation of Power Liftgate
To change the liftgate to
manual operation, press
the switch on the
center console to the OFF
position.
With the power liftgate disabled and all of the doors
unlocked, the liftgate can be manually opened and
closed.To open the liftgate, press the touchpad on the handle
on the outside of the liftgate, and lift the gate open.
To close the liftgate, use the pull cup to lower the liftgate
and close. The liftgate latch will power close. Always
close the liftgate before driving.
If the RKE button or the power close button on the liftgate
is pressed while power operation is disabled, the lights
will ash three times, but the liftgate will not move.
It is not recommended that you drive with the liftgate
open, however, if you must drive with the liftgate open,
the liftgate should be set to manual operation by
pressing the OFF switch on the center console.
The liftgate has an electric latch. If the battery is
disconnected or has low voltage, the liftgate will not
open. The liftgate will resume operation when the battery
is reconnected and charged.
If the battery is properly connected with adequate
voltage, the switch is not disabled, and the liftgate still
will not function, your vehicle should be taken to a
dealer/retailer for service.
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Object Detection Systems
Ultrasonic Rear Parking
Assist (URPA)
If your vehicle has the Ultrasonic Rear Parking Assist
(URPA) system, it helps you park easier and avoid other
vehicles while in REVERSE (R). It operates at speeds
less than 5 mph (8 km/h). It can determine how
close objects are to the rear bumper, up to 8 feet (2.5 m)
behind your vehicle. The distance sensors are located
on the rear bumper.
{CAUTION:
The Ultrasonic Rear Parking Assist (URPA)
system does not replace driver vision. It
cannot detect:
objects that are below the bumper,
underneath the vehicle, or if they are too
close or far from the vehicle
children, pedestrians, bicyclists, or pets.
If you do not use proper care before and while
backing; vehicle damage, injury, or death
could occur. Even with URPA, always check
behind your vehicle before backing up. While
backing, be sure to look for objects and check
your vehicle’s mirrors.
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When the System Does Not Seem to
Work Properly
The driver disables the system.
The parking brake pedal is depressed.
The ultrasonic sensors are not clean. Keep your
vehicle’s rear bumper free of mud, dirt, snow,
ice and slush. For cleaning instructions, see
Washing Your Vehicle on page 5-92.
A trailer was attached to your vehicle, or a bicycle
or an object was hanging out of your liftgate
during your last drive cycle, the red light may
illuminate in the rear display. Once the attached
object is removed, URPA will return to normal
operation.
A tow bar is attached to your vehicle.
The vehicle’s bumper is damaged. Take the vehicle
to your dealer/retailer to repair the system.
Other conditions may affect system performance,
such as vibrations from a jackhammer or the
compression of air brakes on a very large truck.
If the system is still disabled, after driving forward at
least 15 mph (25 km/h), take your vehicle to your
dealer/retailer.
Rear Vision Camera
Your vehicle may have a Rear Vision Camera system.
Read the entire section before using the system.
The rear vision camera system is designed to help the
driver when backing up. See “Rear Vision Camera”
in the Index of the navigation manual.
OnStar®System
OnStar uses several innovative technologies and live
advisors to provide you with a wide range of safety,
security, information, and convenience services. If your
airbags deploy, the system is designed to make an
automatic call to OnStar Emergency advisors who can
request emergency services be sent to your location.
If you lock your keys in the vehicle, call OnStar at
1-888-4-ONSTAR and they can send a signal to unlock
your doors. If you need roadside assistance, press
the OnStar button and they can contact Roadside
Service for you.
2-47

Daytime Running Lamps (DRL)/
Automatic Headlamp System
Daytime Running Lamps (DRL) can make it easier
for others to see the front of your vehicle during the
day. DRL can be helpful in many different driving
conditions, but they can be especially helpful in
the short periods after dawn and before sunset.
Fully functional daytime running lamps are required
on all vehicles rst sold in Canada.
A light sensor on top of the instrument panel makes
the DRL work, so be sure it is not covered.
The DRL system’s automatic headlamp control will
make the low-beam headlamps come on at a reduced
brightness when the following conditions are met:
The ignition is in the ON/RUN position.
The exterior lamps control is in AUTO.
The engine is running.
When the DRL are on, only the low-beam headlamps,
at a reduced level of brightness, will be on. The
headlamps, taillamps, sidemarker, and other lamps
will not be on. The instrument panel and cluster will
also not be lit.
When it is dark enough outside, the low-beam
headlamps will turn off and the headlamps and parking
lamps will turn on. The other lamps that come on
with the headlamps will also come on.When it is bright enough outside, the headlamps will
go off and the DRL will come on.
As with any vehicle, you should turn on the regular
headlamp system when it is needed.
Fog Lamps
Use the fog lamps for better vision in foggy or misty
conditions.
-(Fog Lamps):The fog lamps button is located on
the exterior lamps control. The exterior lamps control
is located on the instrument panel to the left of the
steering column.
The ignition must be on for the fog lamps to work.
Press the exterior lamps button to turn the fog lamps
on or off. A light will come on in the instrument
panel cluster when the fog lamps are in use.
When the headlamps are changed to high-beam, the
fog lamps will turn off. The fog lamps come back
on again when the high-beam headlamps are turned off.
Some localities have laws that require the headlamps
to be on along with the fog lamps.
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