sensor BUICK LACROSSE 2008 Owner's Manual

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 may or may not have roof-rail airbags.
SeeAirbag System on page 1-54. Roof-rail airbags are
intended to inate in moderate to severe side crashes.
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.
Roof-rail airbags are not intended to inate in frontal
impacts, near-frontal impacts, rollovers, or rear impacts.
A roof-rail airbag is intended to deploy on the side of
the vehicle that is struck.
In any particular crash, no one can say whether an airbag
should have inated simply because of the damage to
a vehicle or because of what the repair costs were.
For frontal airbags, ination is determined by what the
vehicle hits, the angle of the impact, and how quickly the
vehicle slows down. For roof-rail airbags, deployment
is determined by the location and severity of the side
impact.
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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 on the instrument panel
when you start your vehicle.
The words ON and OFF
will be visible during the
system check.
If you are using remote start to start your vehicle from
a distance, if equipped, you may not see the system
check. When the system check is complete, either the
word ON or the word OFF will be visible. SeePassenger
Airbag Status Indicator on page 3-34.The passenger sensing system will turn off the right
front passenger’s frontal airbag under certain conditions.
The driver’s airbags are not part of the passenger
sensing system.
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 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.
1-62

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, 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. 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 alsointerfere 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 1-62.
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.
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

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 3 mph (5 km/h). It can determine how
close objects are to the rear bumper, up to 5 feet (1.5 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.
CAUTION: (Continued)
CAUTION: (Continued)
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.
The display is located
above the rear window and
can be seen by looking
over your right shoulder.
URPA uses three color-coded lights to provide distance
and system information.
2-41

How the System Works
URPA comes on automatically when the shift lever is
moved into REVERSE (R). The rear display will
then briey illuminate to let you know the system is
working.
URPA operates only at speeds less than 3 mph
(5 km/h). If you are above this speed, the red light on
the rear display will ash.
To be detected, objects must be at least 10 inches
(25.4 cm) off the ground and below trunk level. Objects
must also be within 5 feet (1.5 m) from your rear
bumper. This distance may be less during warmer or
humid weather.
A single beep will sound the rst time an object is
detected between 20 inches (0.5 m) and 5 feet (1.5 m)
away. Repeated beeping will occur when you are
closer than 20 inches (0.5 m) from the object.The following describes what will occur with the URPA
display as you get closer to a detected object:
Description English Metric
amber light 5 ft 1.5 m
amber/amber lights 40 in 1.0 m
amber/amber/red
lights/continuous beep20 in 0.5 m
amber/amber/red
lights ashing and
continuous beep1 ft 0.3 m
When the System Does Not Seem to
Work Properly
The ultrasonic sensors are not clean, a red URPA
display light may illuminate when the vehicle is in
REVERSE (R). Keep your rear bumper free of mud,
dirt, snow, ice and slush. For cleaning instructions,
seeWashing Your Vehicle on page 5-102.
2-42

2(Headlamps):Turn the control to this position to
turn on the headlamps together with the following lamps
listed below.
A warning chime will sound if the driver’s door is
opened when the ignition switch is turned to LOCK/OFF
or ACC/ACCESSORY and the headlamps or parking
lamps are on.
Parking Lamps
Taillamps
License Plate Lamps
Instrument Panel Lights
-(Foglamps) (If Equipped):Push the fog lamps
button to turn them on and off. SeeFog Lamps on
page 3-15for additional information.
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. DRL lamps are required to
function at all times 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 will make the low-beam headlamps
come on at reduced brightness when the following
conditions are met:
The ignition is on.
The exterior lamps control is off.
The parking brake is released.
While the DRL are on, only the vehicle’s low-beam
headlamps will be on at reduced brightness. The turn
signal, taillamps, sidemarker, and other lamps will not be
on. The instrument panel will not be lit up either.
3-14

Dual Automatic Climate Control
System
With this system you can control the heating, cooling,
and ventilation for the vehicle.
Automatic Operation
AUTO (Automatic):Press the AUTO button for
automatic control of the inside temperature, the air
delivery mode, and the fan speed. There might be a
delay of two to three minutes before the fan comes on
when the automatic operation is used in cold weather.
For the automatic system to function, the temperature
must be set between 61°F (15°C) and 89°F (32°C).1. Adjust the temperature to a comfortable setting.
2. Press the PASS button or the up or down arrows on
the passenger side to turn the passenger
temperature set on and off. When turned on, the
passenger temperature will be the same as the driver
setting. Press the up or down arrow on passenger
side to adjust the passenger temperature setting.
When the passenger’s temperature set is off, the
passenger display will be off and the driver’s
set temperature will be for the driver and passenger.
In cold weather, the system will start at reduced
fan speeds to avoid blowing cold air into the vehicle
until warmer air is available. The system will start
out blowing air at the oor but may change
modes automatically as the vehicle warms up to
maintain the chosen temperature setting. The length
of time needed for warm up will depend on the
outside temperature and the length of time that has
elapsed since the vehicle was last driven.
3. Wait for the system to regulate. This may take from
10 to 30 minutes. Then, adjust the temperature, if
necessary.
Do not cover the solar sensor located in the center
of the instrument panel, near the windshield. For
more information on the solar sensor, see “Sensors”
later in this section.
3-24

Defogging and Defrosting
Fog on the inside of windows is a result of high humidity
(moisture) condensing on the cool window glass. This
can be minimized if the climate control system is
used properly. There are two modes to clear fog or frost
from your windshield. Use the oor/defog mode to
clear the windows of fog or moisture and warm
the passengers. Use defrost to remove fog or frost from
the windshield more quickly.
-(Floor/Defog):Press this button to direct the air
between the windshield, oor outlets and side windows.
When you select this mode, the system turns
recirculation off and runs the air conditioning compressor
unless the outside temperature is near or below
freezing. Pressing the recirculation button will have no
effect other than turning on the indicator light while
in oor/defog mode.
1(Defrost):Press this button to direct most of the
air to the windshield, with some air directed to the
side windows. In this mode, the system will automatically
turn off the recirculation and run the air conditioning
compressor, unless the outside temperature is near or
below freezing. Pressing the recirculation button will
have no effect other than turning on the indicator light
while in defrost mode.
Do not drive the vehicle until all windows are clear.
Sensors
The solar sensor on the vehicle monitors the solar heat
and the air inside of the vehicle. This information is
used to maintain the selected temperature by initiating
needed adjustments to the temperature, the fan
speed, and the air delivery system. The system may
also supply cooler air to the side of the vehicle facing the
sun. The recirculation mode will also be activated, as
necessary. Do not cover the solar sensor located in the
center of the instrument panel, near the windshield,
or the system will not work properly.
3-27

Passenger Safety Belt Reminder Light
Several seconds after the engine is started, a chime
will sound for several seconds to remind the front
passenger to buckle their safety belt. This would only
occur if the passenger airbag is enabled. SeePassenger
Sensing System on page 1-62for more information.
The passenger safety belt light, located on the
instrument panel, will come on and stay on for several
seconds and then ash for several more.
This chime and light are
repeated if the passenger
remains unbuckled and
the vehicle is in motion.
If the passenger’s safety belt is buckled, neither the
chime nor the light will come on.
Airbag Readiness Light
There is an airbag readiness light on the instrument
panel cluster, which shows the airbag symbol. The
system checks the airbag’s electrical system for
malfunctions. The light tells you if there is an electrical
problem. The system check includes the airbag
sensor, the pretensioners, the airbag modules, the
wiring and the crash sensing and diagnostic module.
For more information on the airbag system, seeAirbag
System on page 1-54.
This light will come on
when you start your
vehicle, and it will ash for
a few seconds. The
light should go out and the
system is ready.
3-33

How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
inated simply by looking at them. Radial tires may
look properly inated even when they are
under-inated. Check the tire’s ination pressure
when the tires are cold. Cold means your vehicle
has been sitting for at least three hours or driven no
more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem.
Press the tire gage rmly onto the valve to get a
pressure measurement. If the cold tire ination
pressure matches the recommended pressure on
the Tire and Loading Information label, no further
adjustment is necessary. If the ination pressure is
low, add air until you reach the recommended
amount.
If you overll the tire, release air by pushing on
the metal stem in the center of the tire valve.
Re-check the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
Tire Pressure Monitor System
The Tire Pressure Monitor System (TPMS) uses radio
and sensor technology to check tire pressure levels. The
TPMS sensors monitor the air pressure in your vehicle’s
tires and transmit tire pressure readings to a receiver
located in the vehicle.
Each tire, including the spare (if provided), should be
checked monthly when cold and inated to the ination
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire ination pressure label.
(If your vehicle has tires of a different size than the size
indicated on the vehicle placard or tire ination
pressure label, you should determine the proper tire
ination pressure for those tires.)
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system (TPMS)
that illuminates a low tire pressure telltale when one
or more of your tires is signicantly under-inated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as
soon as possible, and inate them to the proper
pressure. Driving on a signicantly under-inated tire
causes the tire to overheat and can lead to tire failure.
Under-ination also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.
5-71