2009 BUICK LACROSSE sensor

This chime and light are
repeated if the passenger
remains unbuckled and
the vehicle is in motion.
If the passenger safety belt is buckled, neither the
chime nor the light comes on.
The front passenger safety belt warning light and
chime may turn on if an object is put on the seat such
as a briefcase, handbag, grocery bag, laptop or other
electronic device. To turn off the warning light and or
chime, remove the object from the seat or buckle the
safety belt.
Airbag Readiness Light
The system checks the airbag’s electrical system for
possible malfunctions. If the light stays on it indicates
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 1-53.The airbag readiness light
ashes for a few seconds
when the engine is started.
If the light does not come
on then, have it xed
immediately.
{CAUTION:
If the airbag readiness light stays on after the
vehicle is started or comes on while driving, it
means the airbag system might not be working
properly. The airbags in the vehicle might not
inate in a crash, or they could even inate
without a crash. To help avoid injury, have
the vehicle serviced right away.
If there is a problem with the airbag system, an airbag
Driver Information Center (DIC) message can also come
on. SeeDIC Warnings and Messages on page 3-56
for more information.
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.
5-62

Tire Pressure Monitor Operation
This vehicle may have a Tire Pressure Monitor System
(TPMS). The TPMS is designed to warn the driver when
a low tire pressure condition exists. TPMS sensors are
mounted onto each tire and wheel assembly, excluding
the spare tire and wheel assembly. The TPMS sensors
monitor the air pressure in the vehicle’s tires and
transmits the tire pressure readings to a receiver
located in the vehicle.
When a low tire pressure
condition is detected, the
TPMS illuminates the low
tire pressure warning light
located on the instrument
panel cluster.
If your vehicle has the uplevel Driver Information
Center (DIC), a warning message to check the pressure
in a specic tire displays at the same time the low tire
pressure warning light comes on. The low tire pressure
warning light and the DIC warning message come on at
each ignition cycle until the tires are inated to the correct
ination pressure. Vehicles that have the uplevel DICbuttons can also check tire pressure levels by pressing
the gages button. For additional information and details
about the DIC operation and displays seeDIC Operation
and Displays on page 3-48andDIC Warnings and
Messages on page 3-56
The low tire pressure warning light may come on in
cool weather when the vehicle is rst started, and then
turn off as you start to drive. This could be an early
indicator that the air pressure in the tire(s) are getting
low and need to be inated to the proper pressure.
A Tire and Loading Information label, attached to
your vehicle, shows the size of your vehicle’s original
equipment tires and the correct ination pressure for
your vehicle’s tires when they are cold. SeeLoading the
Vehicle on page 4-20, for an example of the Tire and
Loading Information label and its location on your vehicle.
Also seeInflation - Tire Pressure on page 5-61.
Your vehicle’s TPMS system can warn you about a low
tire pressure condition but it does not replace normal
tire maintenance. SeeTire Inspection and Rotation
on page 5-67andTires on page 5-54.
Notice:Liquid tire sealants could damage the Tire
Pressure Monitor System (TPMS) sensors. Sensor
damage caused by using a tire sealant is not covered
by your warranty. Do not use liquid tire sealants.
5-64

TPMS Malfunction Light and Message
The TPMS will not function properly if one or more of
the TPMS sensors are missing or inoperable. When the
system detects a malfunction, the low tire warning light
ashes for about one minute and then stays on for the
remainder of the ignition cycle. If your vehicle has the
uplevel Driver Information Center (DIC), A DIC warning
message is also displayed. The low tire warning light and
DIC warning message come on at each ignition cycle
until the problem is corrected. Some of the conditions
that can cause the malfunction light and DIC message
to come on are:
One of the road tires has been replaced with the
spare tire. The spare tire does not have a TPMS
sensor. The TPMS malfunction light should go off
once you re-install the road tire containing the
TPMS sensor.
The TPMS sensor matching process was started but
not completed or not completed successfully after
rotating the vehicle’s tires. The TPMS malfunction
light should go off once the TPMS sensor matching
process is performed successfully. See “TPMS
Sensor Matching Process” later in this section.
One or more TPMS sensors are missing or
damaged. The TPMS malfunction light should
go off when the TPMS sensors are installed and the
sensor matching process is performed successfully.
See your dealer/retailer for service.
Replacement tires or wheels do not match your
vehicle’s original equipment tires or wheels. Tires
and wheels other than those recommended for your
vehicle could prevent the TPMS from functioning
properly. SeeBuying New Tires on page 5-69.
Operating electronic devices or being near facilities
using radio wave frequencies similar to the TPMS
could cause the TPMS sensors to malfunction.
If the TPMS is not functioning it cannot detect or
signal a low tire condition. See your dealer/retailer
for service if the TPMS malfunction light comes on
and stays on.
5-65

TPMS Sensor Matching Process
Each TPMS sensor has a unique identication code.
Any time you replace one or more of the TPMS sensors
or rotate the vehicle’s tires, the identication codes need
to be matched to the new tire/wheel position. The sensors
are matched, to the tire/wheel positions, in the following
order: driver side front tire, passenger side front tire,
passenger side rear tire, and driver side rear tire using
a TPMS diagnostic tool. See your dealer/retailer for
service.
The TPMS sensors may also be matched to each
tire/wheel position by increasing or decreasing the tire’s
air pressure. When increasing the tire’s pressure, do
not exceed the maximum ination pressure indicated on
the tire’s sidewall. To decrease the tire’s air-pressure
use the pointed end of the valve cap, a pencil-style
air pressure gage, or a key.
You have two minutes to match each tire and wheel
position. If it takes longer than two minutes to match
any tire and wheel position, the matching process
stops and you need to start over.
The TPMS sensor matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the
engine off.3. Press the Remote Keyless Entry (RKE) transmitter’s
LOCK and UNLOCK buttons at the same time for
approximately ve seconds. The horn sounds twice
to signal the receiver is in relearn mode and the
TPMS sensor matching process can begin.
4. Start with the driver side front tire.
5. Remove the valve cap from the tire’s valve
stem. Activate the TPMS sensor by increasing or
decreasing the tire’s air pressure for 10 seconds,
or until a horn chirp sounds. The horn chirp, which
may take up to 30 seconds to sound, conrms that
the sensor identication code has been matched to
the tire/wheel position.
6. Proceed to the passenger side front tire, and repeat
the procedure in Step 5.
7. Proceed to the passenger side rear tire, and repeat
the procedure in Step 5.
8. Proceed to the driver side rear tire, and repeat the
procedure in Step 5.
9. After hearing the conrming horn chirp for the driver
side rear tire, the horn chirps two more times to
signal the tire learning process has ended. Turn
the ignition switch to LOCK/OFF.
10. Set all four tires to the recommended air
pressure level as indicated on the tire and loading
information label.
11. Put the valve caps back on the valve stems.
5-66

Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be necessary
on a regular basis. However, if you notice unusual tire
wear or your vehicle pulling to one side or the other, the
alignment might need to be checked. If you notice your
vehicle vibrating when driving on a smooth road, the tires
and wheels might need to be rebalanced. See your
dealer/retailer for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the wheel,
wheel bolts, and wheel nuts should be replaced. If the
wheel leaks air, replace it (except some aluminum
wheels, which can sometimes be repaired). See your
dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheel
you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset, and be mounted
the same way as the one it replaces.If you need to replace any of your wheels, wheel bolts,
wheel nuts, or Tire Pressure Monitor System (TPMS)
sensors, replace them only with new GM original
equipment parts. This way, you will be sure to have
the right wheel, wheel bolts, wheel nuts, and TPMS
sensors for your vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel bolts,
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make you
lose control. You could have a collision in which
you or others could be injured. Always use the
correct wheel, wheel bolts, and wheel nuts for
replacement.
Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
SeeChanging a Flat Tire on page 5-76for more
information.
5-74

Mini-Fuses Usage
1 Driver Side High-Beam
2 Passenger Side High-Beam
3 Driver Side Low-Beam
4 Passenger Side Low-Beam
5 Windshield Wiper
Mini-Fuses Usage
6 Washer/Regulated Voltage Control
7 Fog Lamps
8 Transmission Control Module
9 Supplemental Inatable Restraint
10 Auxiliary Power
11 Horn
12 Emission
13 Air Conditioner Clutch
14 Oxygen Sensor
15 Powertrain Control Module
16Powertrain Control Module,
Electronic Throttle Control
17 Electronic Throttle Control
18 Display
19 Antilock Brake Solenoid
20 Fuel Injector
21 Transmission Solenoid
22 Fuel Pump
23 Antilock Brake System
24 Ignition 3.8L V6 Engines
5-102