engine BUICK LACROSSE 2012 Repair Manual

Black plate (30,1)Buick LaCrosse Owner Manual - 2012
9-30 Driving and Operating
Engine Exhaust
{WARNING
Engine exhaust contains carbon
monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
.The exhaust smells or
sounds strange or different.
.The exhaust system leaks
due to corrosion or damage.
.The vehicle exhaust system
has been modified, damaged
or improperly repaired.(Continued)
WARNING (Continued)
.There are holes or openings
in the vehicle body from
damage or aftermarket
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.
Running the Vehicle
While Parked
It is better not to park with the
engine running. But if you ever have
to, here are some things to know.
{WARNING
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains Carbon Monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area that
has no fresh air ventilation. For
more information, see Engine
Exhaust on page 9‑30.

Black plate (31,1)Buick LaCrosse Owner Manual - 2012
Driving and Operating 9-31
{WARNING
It can be dangerous to get out of
the vehicle if the automatic
transmission shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll. Do
not leave the vehicle when the
engine is running unless you
have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
Follow the proper steps to be sure
the vehicle will not move. See
Shifting Into Park on page 9‑27.
If parking on a hill and pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑57.
Automatic
Transmission
The automatic transmission has a
shift lever located on the console
between the seats.
P (Park): This position locks the
front wheels. It is the best position
to use when starting the engine
because the vehicle cannot move
easily.
{WARNING
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the
engine is running unless you
have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
See Shifting Into Park on
page 9‑27. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑57.
Make sure the shift lever is fully in
P (Park) before starting the engine.
The vehicle has an automatic
transmission shift lock control
system.

Black plate (32,1)Buick LaCrosse Owner Manual - 2012
9-32 Driving and Operating
The regular brake must be fully
applied first and then the shift lever
button pressed before shifting from
P (Park) when the ignition key is in
ON/RUN. If you cannot shift out of
P (Park), ease pressure on the shift
lever, then push the shift lever all
the way into P (Park) as you
maintain brake application. Then
press the shift lever button and
move the shift lever into another
gear. SeeShifting out of Park on
page 9‑29.
R (Reverse): Use this gear to
back up.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped. To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see
If
the Vehicle Is Stuck on page 9‑11.
N (Neutral): In this position, the
engine does not connect with the
wheels. To restart the engine when
the vehicle is already moving, use
N (Neutral) only. Also, use
N (Neutral) when the vehicle is
being towed.
{WARNING
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed. Notice:
Shifting out of P (Park) or
N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle.
D (Drive): This position is for
normal driving. It provides the best
fuel economy. If more power is
needed for passing, and the
vehicle is:.Going less than 56 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 56 km/h (35 mph) or
more, push the accelerator all
the way down.

Black plate (33,1)Buick LaCrosse Owner Manual - 2012
Driving and Operating 9-33
Notice:If the vehicle seems to
accelerate slowly or not shift
gears when you go faster, and
you continue to drive the vehicle
that way, you could damage the
transmission. Have the vehicle
serviced right away. You can
drive in L (Low) when you are
driving less than 56 km/h (35 mph)
and D (Drive) for higher speeds
until then.
Manual Mode: This position is
shown on the shift lever as a +/−.
It allows the driver to select the
gears appropriate for current driving
conditions. See Manual Mode on
page 9‑33 for more information.
Manual Mode
Driver Shift Control (DSC)
Notice:Driving with the engine at
a high rpm without upshifting
while using Driver Shift Control
(DSC), could damage the vehicle.
Always upshift when necessary
while using DSC. DSC allows you to shift an
automatic transmission similar to a
manual transmission. To use the
DSC feature:
With Selective Ride Control
1. Move the shift lever to the left
from D (Drive).
The vehicle will be in Sport
Mode. The gear indicator in the
DIC will still display a D for
Drive, and the SPORT MODE
ON message will be displayed
momentarily. See Driver
Information Center (DIC) on
page 5‑27. When you are in
Sport Mode, the vehicle will still
shift automatically, but chassis
tuning is modified. See Selective
Ride Control on page 9‑41.
If you move the shift lever
forward or rearward, the
transmission will enter Manual
Mode, and the DIC gear
indicator will change to an M
followed by a number
representing the gear the vehicle
is currently in. 2. In Manual Mode, press the shift
lever forward to upshift or
rearward to downshift.
Without Selective Ride Control
1. Move the shift lever to the left from D (Drive).
The transmission will enter
Manual Mode. The DIC gear
indicator will change to an M
followed by a number
representing the gear the vehicle
is currently in.
2. In Manual Mode, press the shift lever forward to upshift or
rearward to downshift.

Black plate (34,1)Buick LaCrosse Owner Manual - 2012
9-34 Driving and Operating
Uplevel Display Shown, BaseModel Similar
The display on the instrument panel
cluster will show which gear the
vehicle is in. The number indicates
the requested gear range when
moving the shift lever forward or
rearward. The transmission will only allow
you to shift into gears appropriate
for the vehicle speed and engine
revolutions per minute (rpm). The
transmission will not automatically
shift to the next lower gear if the
engine rpm is too high, nor to the
next higher gear when the maximum
engine rpm is reached.
While in the DSC mode, the
transmission will automatically
downshift when the vehicle comes
to a stop. This will allow for more
power during take-off.
When accelerating the vehicle from
a stop in snowy and icy conditions,
you may want to shift into second
gear. A higher gear allows you to
gain more traction on slippery
surfaces.
Drive Systems
All-Wheel Drive
Vehicles with this feature always
send engine power to all four
wheels. It is fully automatic, and
adjusts itself as needed for road
conditions.
When using a compact spare tire on
an AWD vehicle, the system
automatically detects the compact
spare and disables AWD. To restore
AWD operation and prevent
excessive wear on the system,
replace the compact spare with a
full-size tire as soon as possible.
See
Compact Spare Tire on
page 10‑93 for more information.

Black plate (35,1)Buick LaCrosse Owner Manual - 2012
Driving and Operating 9-35
Brakes
Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and the
vehicle begins to drive away, ABS
checks itself. A momentary motor or
clicking noise might be heard while
this test is going on, and it might
even be noticed that the brake
pedal moves a little. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
on page 5‑21. If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses that the wheels
are slowing down. If one of the
wheels is about to stop rolling, the
computer will separately work the
brakes at each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
the driver steer around the obstacle
while braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. You might hear the ABS
pump or motor operating and feel
the brake pedal pulsate, but this is
normal.
Braking in Emergencies
ABS allows the driver to steer and
brake at the same time. In many
emergencies, steering can help
more than even the very best
braking.

Black plate (36,1)Buick LaCrosse Owner Manual - 2012
9-36 Driving and Operating
Parking Brake
The vehicle has an Electric Parking
Brake (EPB). The switch for the
EPB is in the center console. The
EPB can always be activated, even
if the ignition is off. To prevent
draining the battery, avoid repeated
cycles of the EPB system when the
engine is not running.
The system has a parking brake
status light and a parking brake
warning light. SeeElectric Parking
Brake Light on page 5‑21. There are
also three Driver Information Center (DIC) messages. See
Brake System
Messages on page 5‑36 for more
information. In case of insufficient
electrical power, the EPB cannot be
applied or released.
Before leaving the vehicle, check
the parking brake status light to
ensure that the parking brake is
applied.
EPB Apply
The EPB can be applied any time
the vehicle is stopped. The EPB is
applied by momentarily lifting up on
the EPB switch. Once fully applied,
the parking brake status light will be
on. While the brake is being applied,
the status light will flash until full
apply is reached. If the light does
not come on, or remains flashing,
have the vehicle serviced. Do not
drive the vehicle if the parking brake
status light is flashing. See your
dealer. See Electric Parking Brake
Light on page 5‑21 for more
information. If the EPB is applied while the
vehicle is in motion, a chime will
sound, and a DIC message will be
displayed. See
Brake System
Messages on page 5‑36. The
vehicle will decelerate as long as
the switch is held in the up position.
Releasing the EPB switch during
deceleration will release the parking
brake. If the switch is held in the up
position until the vehicle comes to a
stop, the EPB will remain applied.
If the parking brake status light
flashes continuously, the EPB is
only partially applied or released,
or there is a problem with the EPB.
A DIC message will be displayed.
See Brake System Messages on
page 5‑36. If this light flashes
continuously, release the EPB, and
attempt to apply it again. If this light
continues to flash, do not drive the
vehicle. See your dealer.

Black plate (38,1)Buick LaCrosse Owner Manual - 2012
9-38 Driving and Operating
Brake Assist
This vehicle has a brake assist
feature designed to assist the driver
in stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement the
power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle. The
stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time is
normal and the driver should
continue to apply the brake pedal as
the driving situation dictates. The
brake assist feature will
automatically disengage when the
brake pedal is released or brake
pedal pressure is quickly
decreased.
Hill Start Assist (HSA)
This vehicle has a Hill Start Assist
(HSA) feature, which may be useful
when the vehicle is stopped on a
grade. This feature is designed to
prevent the vehicle from rolling,
either forward or rearward, during
vehicle drive off. After the driver
completely stops and holds the
vehicle in a complete standstill on a
grade, HSA will be automatically
activated. During the transition
period between when the driver
releases the brake pedal and starts
to accelerate to drive off on a grade,
HSA holds the braking pressure to
ensure that there is no rolling. The
brakes will automatically release
when the accelerator pedal is
applied within the two‐second
window. It will not activate if the
vehicle is in a drive gear and facing
downhill or if the vehicle is facing
uphill and in R (Reverse).
Ride Control Systems
Traction Control
System (TCS)
The vehicle has a Traction Control
System (TCS) that limits wheel slip.
The system operates if it senses
that one or both of the front wheels
are slipping or beginning to lose
traction. When this happens, the
system reduces engine power and/
or applies brake pressure to the
slipping wheel(s).
The system may be heard or felt
while it is working, but this is
normal.
TCS automatically comes on
whenever the vehicle is started. To
limit wheel slip, especially in
slippery road conditions, the system
should always be left on. But, TCS
can be turned off if needed.

Black plate (39,1)Buick LaCrosse Owner Manual - 2012
Driving and Operating 9-39
dflashes to indicate that TCS is
active. See Traction Control System
(TCS)/StabiliTrak
®Light on
page 5‑23 for more information.
If there is a problem detected with
TCS, SERVICE TRACTION
CONTROL is displayed on the
Driver Information Center (DIC).
See Ride Control System Messages
on page 5‑40. When this message
is displayed and
dcomes on and
stays on, the vehicle is safe to drive
but the system is not operational.
Driving should be adjusted
accordingly.
If
dcomes on and stays on, reset
the system.
To reset:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine. If
dstill comes on and stays on, the
vehicle needs service.
Notice: Do not repeatedly brake
or accelerate heavily when TCS is
off. The vehicle's driveline could
be damaged.
TCS can be turned off by pressing
and releasing the TCS/StabiliTrak
button. When TCS is turned off,
i
comes on, and the appropriate DIC message also displays. See
Ride
Control System Messages on
page 5‑40. With TCS turned off, the
system does not limit wheel slip.
Driving should be adjusted
accordingly. See Traction Off Light
on page 5‑22 for more information.
Press and release the TCS/
StabiliTrak button again to turn the
system back on.
It may be necessary to turn the
system off if the vehicle gets stuck
in sand, mud, or snow and rocking
the vehicle is required. See If the
Vehicle Is Stuck on page 9‑11 for
more information. See also Winter
Driving on page 9‑9 for information
on using TCS when driving in snowy
or icy conditions.
Adding non‐GM accessories can
affect the vehicle performance. See
Accessories and Modifications on
page 10‑3 for more information.

Black plate (40,1)Buick LaCrosse Owner Manual - 2012
9-40 Driving and Operating
StabiliTrak®System
The vehicle may have a vehicle
stability enhancement system called
StabiliTrak. It is an advanced
computer-controlled system that
assists with directional control of the
vehicle in difficult driving conditions.
StabiliTrak activates when the
computer senses a difference
between the intended path and the
direction the vehicle is actually
traveling. StabiliTrak selectively
applies braking pressure to the
vehicle brakes to help steer the
vehicle in the intended direction.
StabiliTrak comes on automatically
whenever the vehicle is started. To
assist with directional control of the
vehicle, the system should always
be left on.
When StabiliTrak activates,
d
flashes on the instrument panel.
A noise may be heard or vibration
may be felt in the brake pedal. This
is normal. Continue to steer the
vehicle in the intended direction.See
Traction Control System (TCS)/
StabiliTrak
®Light on page 5‑23 for
more information.
If a problem is detected with
StabiliTrak, SERVICE
STABILITRAK is displayed on the
Driver Information Center (DIC).
See Ride Control System Messages
on page 5‑40. When this message
is displayed and
dcomes on and
stays on, the vehicle is safe to drive
but the system is not operational.
Driving should be adjusted
accordingly.
If
dcomes on and stays on, reset
the system.
To reset:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
If
dstill comes on and stays on, the
vehicle needs service.
.To turn off both StabiliTrak and
TCS, press and hold the TCS/
StabiliTrak button, located on the
instrument panel, until
iandg
illuminate and the appropriate
DIC message is displayed. See
Ride Control System Messages
on page 5‑40.