ignition BUICK LACROSSE 2015 Service Manual

Black plate (6,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
6-6 Lighting
Reading Lamps
There are front and rear reading
lamps.
The front reading lamps are in the
overhead console.
The rear reading lamps are in the
headliner.
#or$(Reading Lamps):Press
to turn each lamp on or off.
Sun Visor Lamps
This lamp turns on when the cover
is opened.
Lighting Features
Entry Lighting
The headlamps, taillamps, license
plate lamps, back-up lamps, dome
lamps, and most of the interior lights
turn on briefly when the Remote
Keyless Entry (RKE) transmitter
K
button is pressed. See Ignition
Positions (Key Access) on
page 9-15 orIgnition Positions
(Keyless Access) on page 9-16.
After about 30 seconds the exterior
lamps turn off, then the dome lamps
and remaining interior lights dim to
off. Entry lighting can be disabled
manually by changing the ignition
out of the OFF position, or by
pressing the RKE transmitter
Q
button.
This feature can be changed. See
Vehicle Personalization on
page 5-45.

Black plate (7,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Lighting 6-7
Exit Lighting
The headlamps, taillamps, back-up
lamps, parking lamps, and license
plate lamps come on at night, or in
areas with limited lighting, when the
key is removed from the ignition.
The dome lamps also come on
when the key is removed from the
ignition. The exterior lamps and
dome lamps remain on after the
door is closed for a set amount of
time, then automatically turn off.
If equipped with Keyless Access,
the exterior lamps and dome lamps
automatically turn on when the
driver door is opened after the
ignition is turned off. SeeIgnition
Positions (Key Access) on
page 9-15 orIgnition Positions
(Keyless Access) on page 9-16.
The exterior lamps turn off
immediately by turning the exterior
lamp control off.
This feature can be changed. See
Vehicle Personalization on
page 5-45.
Battery Load
Management
The vehicle has Electric Power
Management (EPM) that estimates
the battery's temperature and state
of charge. It then adjusts the voltage
for best performance and extended
life of the battery.
When the battery's state of charge
is low, the voltage is raised slightly
to quickly bring the charge back up.
When the state of charge is high,
the voltage is lowered slightly to
prevent overcharging. If the vehicle
has a voltmeter gauge or a voltage
display on the Driver Information
Center (DIC), you may see the
voltage move up or down. This is
normal. If there is a problem, an
alert will be displayed.
The battery can be discharged at
idle if the electrical loads are very
high. This is true for all vehicles.
This is because the generator
(alternator) may not be spinning fast enough at idle to produce all of the
power needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, fog
lamps, rear window defogger,
climate control fan at high speed,
heated seats, engine cooling fans,
trailer loads, and loads plugged into
accessory power outlets.
EPM works to prevent excessive
discharge of the battery. It does this
by balancing the generator's output
and the vehicle's electrical needs.
It can increase engine idle speed to
generate more power whenever
needed. It can temporarily reduce
the power demands of some
accessories.
Normally, these actions occur in
steps or levels, without being
noticeable. In rare cases at the
highest levels of corrective action,
this action may be noticeable to the
driver. If so, a DIC message might
be displayed and it is recommended

Black plate (8,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
6-8 Lighting
that the driver reduce the electrical
loads as much as possible. See
Battery Voltage and Charging
Messages on page 5-35.
Battery Power Protection
The battery saver feature is
designed to protect the vehicle's
battery.
If the exterior lamps or any interior
light is left on and the ignition is
turned off, the battery rundown
protection system automatically
turns the lamp off after about
10 minutes.

Black plate (4,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
8-4 Climate Controls
The indicator will be lit green in eco,
amber in comfort, and turns off
when there is no A/C function. If the
fan is turned off the A/C will not run.
The eco A/C setting balances fuel
economy and air conditioning
comfort. In warm weather
conditions, auto stops may occur
more frequently and the vehicle
interior may be warmer as
compared to the comfort air
conditioning. This setting allows
higher humidity inside the vehicle
and window fogging before the
engine restarts.
Pressing the
0button during an
auto stop may restart the engine to
prevent window fogging. To reach
comfort levels quickly during an
auto stop, the engine will restart if
the air conditioner is off and AUTO
or A/C is selected.
If temperature controls are adjusted
cooler by more than 1°C (1°F)
during an auto stop, the engine will
restart to ensure that comfort is
reached.
@(Recirculation): Press to turn
on recirculation. An indicator light
comes on. Air is recirculated to
quickly cool the air inside the
vehicle or prevent odors from
entering. Press again to change to
outside air and the indicator light
turns off.
Press AUTO to return to automatic
operation and recirculation runs
automatically as needed. The
indicator light is off.
The Air Quality Sensor may operate
the recirculation mode automatically.
See “Climate and Air Quality” under
Vehicle Personalization on
page 5-45.
Auto Defog: The climate control
system may have a sensor to
automatically detect high humidity
inside the vehicle. When high
humidity is detected, the climate
control system may adjust to
outside air supply and turn on the
air conditioner. The fan speed may
slightly increase to help prevent
fogging. If the climate control system does not detect possible
window fogging, it returns to normal
operation. For eAssist vehicles,
there may be shorter and less
frequent auto stops when auto
defog is in use.
To turn Auto Defog off or on, see
“Climate and Air Quality”
under
Vehicle Personalization on
page 5-45.
Rear Window Defogger
=(Rear Window Defogger):
Press to turn the rear window
defogger on or off. An indicator light
on the button comes on to show that
the rear window defogger is on.
The defogger can be turned off by
turning the ignition to ACC/
ACCESSORY or LOCK/OFF.
The rear window defogger can be
set to automatic operation. See
“Climate and Air Quality” under
Vehicle Personalization on
page 5-45. When auto rear defog is
selected, the rear window defogger
turns on automatically when the

Black plate (1,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Driving and Operating 9-1
Driving and
Operating
Driving Information
Distracted Driving . . . . . . . . . . . . . 9-2
Defensive Driving . . . . . . . . . . . . . 9-3
Drunk Driving . . . . . . . . . . . . . . . . . 9-3
Control of a Vehicle . . . . . . . . . . . 9-3
Braking . . . . . . . . . . . . . . . . . . . . . . . 9-3
Steering . . . . . . . . . . . . . . . . . . . . . . . 9-4
Off-Road Recovery . . . . . . . . . . . . 9-5
Loss of Control . . . . . . . . . . . . . . . . 9-6
Driving on Wet Roads . . . . . . . . . 9-6
Hill and Mountain Roads . . . . . . 9-7
Winter Driving . . . . . . . . . . . . . . . . . 9-8
If the Vehicle Is Stuck . . . . . . . . . 9-9
Vehicle Load Limits . . . . . . . . . . 9-10
Starting and Operating
New Vehicle Break-In . . . . . . . . 9-14
Ignition Positions (KeyAccess) . . . . . . . . . . . . . . . . . . . . 9-15
Ignition Positions (Keyless Access) . . . . . . . . . . . . . . . . . . . . 9-16
Starting the Engine . . . . . . . . . . 9-18
Engine Heater . . . . . . . . . . . . . . . 9-22 Retained Accessory
Power (RAP) . . . . . . . . . . . . . . . 9-23
Shifting Into Park . . . . . . . . . . . . 9-24
Shifting out of Park . . . . . . . . . . 9-25
Parking over Things That Burn . . . . . . . . . . . . . . . . . . 9-25
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . 9-26
Running the Vehicle WhileParked . . . . . . . . . . . . . . . . . . . . . 9-26
Automatic Transmission
Automatic Transmission . . . . . 9-27
Manual Mode . . . . . . . . . . . . . . . . 9-29
Drive Systems
All-Wheel Drive . . . . . . . . . . . . . . 9-30
Brakes
Antilock BrakeSystem (ABS) . . . . . . . . . . . . . . 9-30
Parking Brake . . . . . . . . . . . . . . . 9-31
Brake Assist . . . . . . . . . . . . . . . . . 9-33
Hill Start Assist (HSA) . . . . . . . 9-33
Ride Control Systems
Traction Control/Electronic Stability Control . . . . . . . . . . . . 9-34
Limited-Slip Differential . . . . . . 9-36
Selective Ride Control . . . . . . . 9-36
Cruise Control
Cruise Control . . . . . . . . . . . . . . . 9-37
Adaptive Cruise Control . . . . . 9-39
Driver Assistance Systems
Driver Assistance Systems . . . . . . . . . . . . . . . . . . . . 9-47
Assistance Systems for Parking or Backing . . . . . . . . . 9-48
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . 9-50
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . 9-50
Active Emergency Braking System . . . . . . . . . . . . . . . . . . . . . 9-53
Side Blind Zone Alert (SBZA) . . . . . . . . . . . . . . . 9-54
Lane Change Alert . . . . . . . . . . . 9-55
Lane Departure Warning (LDW) . . . . . . . . . . . . . 9-57

Black plate (7,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Driving and Operating 9-7
Warning (Continued)
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is
wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping
equipment in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper
tread depth. SeeTires on
page 10-42.
.Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips for
driving in these conditions include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and
loss of steering. Always have the
engine running and the vehicle
in gear.

Black plate (15,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Driving and Operating 9-15
Caution (Continued)
breaking-in guideline every
time you get new brake
linings.
Following break-in, engine speed
and load can be gradually
increased.
Ignition Positions (Key
Access)
{Caution
Using a tool to force the key to
turn in the ignition could cause
damage to the switch or break the
key. Use the correct key, make
sure it is all the way in, and turn it
only with your hand. If the key
cannot be turned by hand, see
your dealer.
The key must be fully extended to
start the vehicle.
To shift out of P (Park), turn the
ignition to ON/RUN and apply the
brake pedal.
1 (STOPPING THE ENGINE/LOCK/
OFF): When the vehicle is stopped,
turn the ignition switch to LOCK/
OFF to turn the engine off. Retained
Accessory Power (RAP) will remain
active. See Retained Accessory
Power (RAP) on page 9-23 for more
information. This is the only position from which
the key can be removed. This locks
the ignition and automatic
transmission.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady
pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to a
safe location.
3. Come to a complete stop, shift to P (Park), and turn the ignition
to LOCK/OFF. On vehicles with
an automatic transmission, the

Black plate (16,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
9-16 Driving and Operating
shift lever must be in P (Park) to
turn the ignition switch to the
LOCK/OFF position.
4. Set the parking brake. See Parking Brake on page 9-31.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
turn the ignition to ACC/
ACCESSORY.
2 (ACC/ACCESSORY): This
position provides power to some of
the electrical accessories. It unlocks
the ignition. To move the key from
ACC/ACCESSORY to LOCK/OFF,
the shift lever must be in P (Park). 3 (ON/RUN):
The ignition switch
stays in this position when the
engine is running. This position can
be used to operate the electrical
accessories, including the
ventilation fan and 12-volt power
outlet, as well as to display some
warning and indicator lights. This
position can also be used for
service and diagnostics, and to
verify the proper operation of the
malfunction indicator lamp as may
be required for emission inspection
purposes. The transmission is also
unlocked in this position.
The battery could be drained if the
key is left in the ACC/ACCESSORY
or ON/RUN position with the engine
off. The vehicle might not restart if
the battery is allowed to drain for an
extended period of time.
4 (START): This position starts the
engine. When the engine starts,
release the key. The ignition switch
will return to ON/RUN for normal
driving. A warning tone sounds when the
driver door is opened when the
ignition is still in ACC/ACCESSORY
and the key is in the ignition. If the
ignition becomes difficult to turn,
see
Keys on page 2-1.
Ignition Positions
(Keyless Access)
The vehicle has an electronic
keyless ignition with pushbutton
start.

Black plate (17,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Driving and Operating 9-17
Pressing the button cycles it through
three modes, ACC/ACCESSORY,
ON/RUN/START, and Stopping the
Engine/OFF.
The transmitter must be in the
vehicle for the system to operate.
If the pushbutton start is not
working, the vehicle may be near a
strong radio antenna signal causing
interference to the keyless access
system. SeeRemote Keyless Entry
(RKE) System Operation on
page 2-3.
To shift out of P (Park), the vehicle
must be in ACC/ACCESSORY or
ON/RUN and the brake pedal must
be applied.
Stopping the Engine/OFF (No
Indicator Lights): When the
vehicle is stopped, press the
ENGINE START/STOP button once
to turn the engine off.
If the vehicle is in P (Park), the
ignition will turn off, and Retained
Accessory Power (RAP) will remain
active. See Retained Accessory
Power (RAP) on page 9-23. If the vehicle is not in P (Park), the
ignition will return to ACC/
ACCESSORY and display the
message SHIFT TO PARK in the
Driver Information Center (DIC).
See
Transmission Messages on
page 5-44. When the vehicle is
shifted into P (Park), the ignition
system will switch to OFF.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to a
safe location. 3. Come to a complete stop, shift
to P (Park), and turn the ignition
to OFF. On vehicles with an
automatic transmission, the shift
lever must be in P (Park) to turn
the ignition switch to the OFF
position.
4. Set the parking brake. See Parking Brake on page 9-31.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
press and hold the ENGINE START/
STOP button for longer than
two seconds, or press twice in
five seconds.

Black plate (18,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
9-18 Driving and Operating
ACC/ACCESSORY (Amber
Indicator Light):This mode allows
you to use some electrical
accessories when the engine is off.
With the ignition off, pressing the
button one time without the brake
pedal applied will place the ignition
system in ACC/ACCESSORY.
The ignition will switch from ACC/
ACCESSORY to OFF after
five minutes to prevent battery
rundown.
ON/RUN/START (Green Indicator
Light): This mode is for driving and
starting. With the ignition off, and
the brake pedal applied, pressing
the button once will place the
ignition system in ON/RUN/START.
Once engine cranking begins,
release the button. Engine cranking
will continue until the engine starts.
See Starting the Engine on
page 9-18. The ignition will then
remain in ON/RUN. Service Only Mode
This power mode is available for
service and diagnostics, and to
verify the proper operation of the
malfunction indicator lamp as may
be required for emission inspection
purposes. With the vehicle off, and
the brake pedal not applied,
pressing and holding the button for
more than five seconds will place
the vehicle in Service Only Mode.
The instruments and audio systems
will operate as they do in ON/RUN,
but the vehicle will not be able to be
driven. The engine will not start in
Service Only Mode. Push the button
again to turn the vehicle off.
Starting the Engine
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.
{Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
{Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See
Add-On Electrical Equipment
on page 9-68.