2012 BUICK LACROSSE service

Black plate (34,1)Buick LaCrosse Owner Manual - 2012
3-34 Seats and Restraints
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the
vehicle's frame, bumper system,
height, front end or side sheet
metal, may keep the airbag system
from working properly. The
operation of the airbag system can
also be affected by 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, or airbag wiring.
Your dealer and the service manual
have information about the location
of the airbag sensors, sensing and
diagnostic module, and airbag
wiring.In addition, the vehicle has a
passenger sensing system for the
front outboard passenger position,
which includes sensors that are part
of the passenger 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 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).
See
Passenger Sensing System on
page 3‑29. If your vehicle needs to be modified
because you have a disability and
you have questions about whether
the modifications will affect the
vehicle's airbag system, or if you
have questions about whether the
airbag system will be affected if the
vehicle is modified for any other
reason, call Customer Assistance.
See
Customer Assistance Offices
(U.S. and Canada) on page 13‑5 or
Customer Assistance Offices
(Mexico) on page 13‑5.

Black plate (35,1)Buick LaCrosse Owner Manual - 2012
Seats and Restraints 3-35
Airbag System Check
The airbag system does not need
regularly scheduled maintenance or
replacement. Make sure the airbag
readiness light is working. See
Airbag Readiness Light on
page 5‑16for 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 airbags, see
Where Are the Airbags? on
page 3‑24. See your dealer for
service.
Replacing Airbag System
Parts after a Crash
{WARNING
A crash can damage the airbag
systems in the vehicle.
A damaged airbag system may
not work properly and may not
protect you and your
passenger(s) in a crash, resulting
in serious injury or even death. To
help make sure the airbag
systems are working properly
after a crash, have them
inspected and any necessary
replacements made as soon as
possible.
If an airbag inflates, you will need to
replace airbag system parts. See
your dealer for service.
If the airbag readiness light stays on
after the vehicle is started or comes
on when you are driving, the airbag
system may not work properly. Have the vehicle serviced right
away. See
Airbag Readiness Light
on page 5‑16 for more information.
Vehicles with eAssist have a high
voltage battery and a standard
12‐volt battery. If an airbag inflates
or the vehicle has been in a crash,
the vehicle's sensing system may
shut down the high voltage system.
When this occurs, the high voltage
battery is disconnected and the
vehicle is not charging the 12‐volt
battery or the electrical system. The
vehicle may start but it shuts down
once the 12‐volt battery is depleted.
When the 12‐volt battery is
depleted, the vehicle will not start
and the on‐board jump start feature
is disabled. The airbag readiness
light and/or the 12‐volt battery
warning light are displayed. Before
the vehicle can be operated again, it
must be serviced at your dealer.

Black plate (13,1)Buick LaCrosse Owner Manual - 2012
Instruments and Controls 5-13
When the ignition is on, the fuel
gauge indicates about how much
fuel is left in the tank.
An arrow on the fuel gauge
indicates the side of the vehicle the
fuel door is on.
When the indicator nears empty, the
low fuel light comes on. There is still
a little fuel left, but the fuel tank
should be filled soon.
Here are four things that some
owners ask about. None of these
show a problem with the fuel gauge:
.At the service station, the fuel
pump shuts off before the gauge
reads full.
.It takes a little more or less fuel
to fill up than the gauge
indicated. For example, the
gauge indicated the tank was
half full, but it actually took a
little more or less than half the
tank's capacity to fill the tank.
.The gauge moves a little while
turning a corner or speeding up.
.The gauge takes a few seconds
to stabilize after the ignition is
turned on, and goes back to
empty when the ignition is
turned off.
Driver Efficiency Gauge
For eAssist vehicles, this gauge
assists in driving efficiently and will
vary based on driver input.To maximize efficiency, keep the
gauge pointed in the solid green
zone in the center of the gauge.
The gauge moves to the left when
braking and to the right when
accelerating. When either is done
aggressively, the vehicle is being
driven less efficiently and the gauge
will move further from the center.

Black plate (16,1)Buick LaCrosse Owner Manual - 2012
5-16 Instruments and Controls
Airbag Readiness Light
This light shows if there is an
electrical problem. The system
check includes the airbag sensor(s),
passenger sensing system, 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 3‑22.
The airbag readiness light comes on
and stays on for several seconds
when the vehicle is started. Then
the light goes out.
{WARNING
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 inflate in a
crash, or they could even inflate
without a crash. To help avoid
injury, have the vehicle serviced
right away.
Passenger Airbag Status
Indicator
The vehicle has a passenger
sensing system. See Passenger
Sensing System on page 3‑29 for
important safety information. The
instrument panel has a passenger
airbag status indicator.
When the vehicle is started, the
passenger airbag status indicator
will light ON and OFF for several
seconds as a system check.
If you are using remote start,
if equipped, to start the vehicle from
a distance, you may not see the
system check. Then, after several
more seconds, the status indicator
will light either ON or OFF to let you
know the status of the front
outboard passenger frontal airbag.
If the word ON is lit on the
passenger airbag status indicator, it
means that the front outboard
passenger frontal airbag is allowed
to inflate.

Black plate (17,1)Buick LaCrosse Owner Manual - 2012
Instruments and Controls 5-17
If the word OFF is lit on the airbag
status indicator, it means that the
passenger sensing system has
turned off the front outboard
passenger frontal airbag.
If, after several seconds, both status
indicator lights remain on, or if there
are no lights at all, there may be a
problem with the lights or the
passenger sensing system. See
your dealer for service.
{WARNING
If the airbag readiness light ever
comes on and stays on, it means
that something may be wrong
with the airbag system. To help
avoid injury to yourself or others,
have the vehicle serviced right
away. SeeAirbag Readiness
Light on page 5‑16 for more
information, including important
safety information.
Charging System Light
The charging system light comes on
briefly when the ignition is turned
on, but the engine is not running, as
a check to show the light is working.
The light turns off when the engine
is started. If it does not, have the
vehicle serviced by your dealer.
If the light stays on, or comes on
while driving, there could be a
problem with the electrical charging
system. Have it checked by your
dealer. Driving while this light is on
could drain the battery.
If a short distance must be driven
with the light on, be sure to turn off
all accessories, such as the radio
and air conditioner.
Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors the operation
of the vehicle to ensure emissions
are at acceptable levels, to produce
a cleaner environment.
This light comes on when the
vehicle is placed in ON/RUN for key
access or Service Only Mode for
keyless access, as a check to show
it is working. If it does not, have the
vehicle serviced by your dealer. See
Ignition Positions (Key Access) on
page 9‑18 orIgnition Positions
(Keyless Access) on page 9‑20 for
more information.

Black plate (18,1)Buick LaCrosse Owner Manual - 2012
5-18 Instruments and Controls
If the malfunction indicator lamp
comes on and stays on while the
engine is running, this indicates that
there is an OBD II problem and
service is required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the dealer technician in correctly
diagnosing any malfunction.
Notice:If the vehicle is
continually driven with this light
on, the emission controls might
not work as well, the vehicle fuel
economy might not be as good,
and the engine might not run as
smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty. Notice:
Modifications made to the
engine, transmission, exhaust,
intake, or fuel system of the
vehicle or the replacement of the
original tires with other than
those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this light
to come on. Modifications to
these systems could lead to
costly repairs not covered by the
vehicle warranty. This could also
result in a failure to pass a
required Emission Inspection/
Maintenance test. See
Accessories and Modifications on
page 10‑3.
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required. To prevent more serious damage to
the vehicle:
.Reduce vehicle speed.
.Avoid hard accelerations.
.Avoid steep uphill grades.
.If the vehicle is towing a trailer,
reduce the amount of cargo
being hauled as soon as it is
possible.
If the light continues to flash, when
it is safe to do so, stop the vehicle.
Find a safe place to park. Turn the
vehicle off, wait at least 10 seconds,
and restart the engine. If the light is
still flashing, follow the previous
steps and see your dealer for
service as soon as possible.
Light On Steady: An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required.

Black plate (19,1)Buick LaCrosse Owner Manual - 2012
Instruments and Controls 5-19
The following may correct an
emissions system malfunction:
.Check that the fuel cap is fully
installed. SeeFilling the Tank on
page 9‑55. The diagnostic
system can determine if the fuel
cap has been left off or
improperly installed. A loose or
missing fuel cap allows fuel to
evaporate into the atmosphere.
A few driving trips with the cap
properly installed should turn the
light off.
.Check that good quality fuel is
used. Poor fuel quality causes
the engine not to run as
efficiently as designed and may
cause stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up. If one or more of these conditions
occurs, change the fuel brand used.
It will require at least one full tank of
the proper fuel to turn the light off.
See
Recommended Fuel on
page 9‑53.
If none of the above have made the
light turn off, your dealer can check
the vehicle. The dealer has the
proper test equipment and
diagnostic tools to fix any
mechanical or electrical problems
that might have developed.Emissions Inspection and
Maintenance Programs
Some local governments may have
programs to inspect the on-vehicle
emission control equipment. For the
inspection, the emission system test
equipment is connected to the
vehicle’s Data Link
Connector (DLC).
The DLC is under the instrument
panel next to the steering wheel.
See your dealer if assistance is
needed.
The vehicle may not pass
inspection if:
.The malfunction indicator lamp is
on while the vehicle is running.
The vehicle is in ON/RUN for
keyed access, or service only
mode for keyless access and the
malfunction indicator lamp does
not come on. See your dealer for
assistance in verifying proper
operation of the malfunction
indicator lamp.

Black plate (20,1)Buick LaCrosse Owner Manual - 2012
5-20 Instruments and Controls
.The OBD II (On-Board
Diagnostics) system determines
that critical emission control
systems have not been
completely diagnosed. The
vehicle would be considered not
ready for inspection. This can
happen if the 12-volt battery has
recently been replaced or run
down. The diagnostic system is
designed to evaluate critical
emission control systems during
normal driving. This can take
several days of routine driving.
If this has been done and the
vehicle still does not pass the
inspection for lack of OBD II
system readiness, your dealer
can prepare the vehicle for
inspection.Brake System Warning
Light
The vehicle brake system consists
of two hydraulic circuits. If one
circuit is not working, the remaining
circuit can still work to stop the
vehicle. For normal braking
performance, both circuits need to
be working.
If the warning light comes on, there
is a brake problem. Have your brake
system inspected right away.
MetricEnglish
If the vehicle has antilock brakes,
this light should come on when the
vehicle is placed in START. If it does
not, have the vehicle serviced by
your dealer. If the light comes on while driving,
pull off the road and stop carefully.
The pedal may be harder to push or
it can go closer to the floor. It may
take longer to stop. Try turning off
and restarting the vehicle one or
two times. If the light is still on, have
the vehicle towed for service. See
Antilock Brake System (ABS)
Warning Light on page 5‑21
and
Towing the Vehicle on page 10‑99.
{WARNING
The brake system might not be
working properly if the brake
system warning light is on.
Driving with the brake system
warning light on can lead to a
crash. If the light is still on after
the vehicle has been pulled off
the road and carefully stopped,
have the vehicle towed for
service.