
Black plate (20,1)Buick LaCrosse Owner Manual - 2012
9-20 Driving and Operating
Ignition Positions
(Keyless Access)
The vehicle has an electronic
keyless ignition with pushbutton
start.
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. See
Remote Keyless Entry
(RKE) System Operation on
page 2‑4 for more information.
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 LED
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 9‑27 for more
information. 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 5‑42 for more information.
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.

Black plate (21,1)Buick LaCrosse Owner Manual - 2012
Driving and Operating 9-21
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
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 9‑36.
{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,
switch the ignition to ACC/
ACCESSORY.
ACC/ACCESSORY (Amber LED
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 LED
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 9‑22 for more information. 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.

Black plate (1,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-3
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil . . . . . . . . . . . . . . . . . . . 10-9
Engine Oil Life System . . . . . 10-12
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-13
Engine Air Cleaner/Filter . . . . 10-13
Cooling System . . . . . . . . . . . . 10-15
Engine Coolant . . . . . . . . . . . . . 10-16
Engine Overheating . . . . . . . . 10-19
Overheated Engine Protection
Operating Mode . . . . . . . . . . . 10-21 Power Steering Fluid (2.4L
L4 Engine) . . . . . . . . . . . . . . . . 10-21
Power Steering Fluid (3.6L V6 Engine) . . . . . . . . . . . . . . . . 10-21
Washer Fluid . . . . . . . . . . . . . . . 10-22
Brakes . . . . . . . . . . . . . . . . . . . . . 10-23
Brake Fluid . . . . . . . . . . . . . . . . . 10-24
Battery . . . . . . . . . . . . . . . . . . . . . 10-25
Starter Switch Check . . . . . . . 10-27
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-27
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-28
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-28
Wiper Blade Replacement . . . . . . . . . . . . . . 10-29
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-30
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-33
Halogen Bulbs . . . . . . . . . . . . . . 10-33
High Intensity Discharge(HID) Lighting . . . . . . . . . . . . . 10-33 Headlamps, Front Turn
Signal and Parking
Lamps . . . . . . . . . . . . . . . . . . . . 10-33
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-35
License Plate Lamp . . . . . . . . 10-36
Replacement Bulbs . . . . . . . . . 10-36
Electrical System
High Voltage Devices and Wiring . . . . . . . . . . . . . . . . . . . . . 10-37
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-37
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-38
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . 10-38
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-42
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-44
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . 10-47
Winter Tires . . . . . . . . . . . . . . . . 10-48
Tire Sidewall Labeling . . . . . . 10-48
Tire Designations . . . . . . . . . . . 10-51

Black plate (9,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-9
A.Engine Air Cleaner/Filter on
page 10‑13.
B. Power Steering Reservoir and Cap. See Power Steering Fluid
(2.4L L4 Engine) on page 10‑21
or Power Steering Fluid (3.6L
V6 Engine) on page 10‑21.
C. Engine Oil Fill Cap. See Engine
Oil on page 10‑9.
D. Engine Oil Dipstick. See Engine
Oil on page 10‑9.
E. Engine Cover.
F. Transmission Fluid Cap and Dipstick. See Automatic
Transmission Fluid on
page 10‑13. G. Brake Master Cylinder
Reservoir. See Brakes on
page 10‑23.
H. Coolant Surge Tank and Pressure Cap. See Engine
Coolant on page 10‑16.
I. Battery Cover. See Battery on
page 10‑25.
J. Engine Compartment Fuse
Block on page 10‑38.
K. Windshield Washer Fluid Reservoir. See Washer Fluid on
page 10‑22.Engine Oil
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
.Always use engine oil approved
to the proper specification and of
the proper viscosity grade. See
“Selecting the Right Engine Oil”
in this section.
.Check the engine oil level
regularly and maintain the
proper oil level. See “Checking
Engine Oil” and“When to Add
Engine Oil” in this section.
.Change the engine oil at the
appropriate time. See Engine Oil
Life System on page 10‑12.
.Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.

Black plate (21,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-21
Overheated Engine
Protection
Operating Mode
This emergency operating mode
allows the vehicle to be driven to a
safe place in an emergency
situation. If an overheated engine
condition exists, an overheat
protection mode which alternates
firing groups of cylinders helps
prevent engine damage. In this
mode, there is significant loss in
power and engine performance.
2.4L L4 Engine
The engine coolant temperature
warning light comes on the
instrument panel, to indicate the
vehicle has entered overheated
engine protection operating mode.
Driving extended distances and/or
towing a trailer in the overheat
protection mode should be avoided.3.6L V6 Engine
The engine coolant temperature
warning light comes on the
instrument panel, to indicate the
vehicle has entered overheated
engine protection operating mode.
The temperature gauge also
indicates an overheat condition
exists. Driving extended distances
and/or towing a trailer in the
overheat protection mode should be
avoided.
Power Steering Fluid
(2.4L L4 Engine)
The vehicle has electric power
steering and does not use power
steering fluid.
Power Steering Fluid
(3.6L V6 Engine)
See
Engine Compartment Overview
on page 10‑6 for information on the
location of the power steering fluid
reservoir.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless a
leak is suspected in the system or
an unusual noise is heard. A fluid
loss in this system could indicate a
problem. Have the system inspected
and repaired.

Black plate (22,1)Buick LaCrosse Owner Manual - 2012
10-22 Vehicle Care
How to Check Power Steering
Fluid
Check the level after the vehicle has
been driven for at least 20 minutes
so the fluid is warm.
To check the power steering fluid:
1. Turn the ignition to LOCK/OFFand let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and pull it straight up.
4. Wipe the dipstick with a clean rag.
5. Replace the cap and completely tighten it.
6. Remove the cap again and look at the fluid level on the dipstick.
When the engine is hot, the level
should be at the hot MAX level.
When the engine is cold, the fluid
level should be between MIN and
MAX on the dipstick.
What to Use
To determine what kind of fluid to
use, see Recommended Fluids and
Lubricants on page 11‑12. Always
use the proper fluid.
Washer Fluid
What to Use
When windshield washer fluid is
needed, be sure to read the
manufacturer's instructions before
use. If operating the vehicle in an
area where the temperature may fall
below freezing, use a fluid that has
sufficient protection against
freezing.
Adding Washer Fluid
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. See Engine
Compartment Overview on
page 10‑6 for reservoir location.

Black plate (40,1)Buick LaCrosse Owner Manual - 2012
10-40 Vehicle Care
Mini Fuses Usage1 Transmission
Control
Module
—Battery
2 Engine Control
Module Battery
3 Air Conditioning
Compressor Clutch
5 Engine Control
Module Run/Crank
8 Ignition
Coils
—Even (Six
Cylinder Engine),
Ignition Coils —All
(Four Cylinder
Engine
9 Ignition Coils
—Odd
(Six Cylinder
Engine)
10 Engine Control
Module
—Switched
Battery (from Engine
Control Module
Relay) Mini Fuses Usage
11 Six Cylinder Engine:
Post Catalytic
Converter Oxygen
Sensor Heater,
Mass Air Flow
Sensor, Flex Fuel
Sensor
13 Run/Crank for
Transmission
Control Module and
Fuel System Control
Module
14 Cabin Heater
Coolant Pump
(eAssist)
15 Motor Generator
Unit Coolant Pump
(eAssist)
16 Run/Crank for
eAssist Power
Inverter Module
17 Airbag
Module
—Run/
Crank Mini Fuses Usage
18 Vented Seats
(eAssist)
23 Variable Effort
Steering
(if equipped) or
eAssist Power
Inverter Module
29 Power Lumbar, Left
30 Power Lumbar,
Right or Power Pack
Cooling Fan
(eAssist)
31 Passive Entry/
Passive Start
Module
—Battery 1
(eAssist)
32 Body Control
Module 6
33 Heated
Seat
—Front
34 Antilock Brake
System Valves
35 Amplifier

Black plate (43,1)Buick LaCrosse Owner Manual - 2012
Vehicle Care 10-43
Instrument Panel Fuse Block
The vehicle may not be equipped
with all of the fuses, relays, and
features shown. Fuses Usage
1 Steering Wheel
Controls Backlight
2 Body Control
Module 7
3 Body Control
Module 5
4 Radio
5 OnStar
6 Power Outlet 1
7 Power Outlet 2
8 Body Control
Module 1
9 Body Control
Module 4
10 Body Control
Module 8
(J‐Case Fuse) Fuses Usage
11 Front Heater
Ventilation Air
Conditioning/Blower
(J‐Case Fuse)
12 Passenger Seat
(Circuit Breaker)
13 Driver Seat (Circuit
Breaker)
14 Diagnostic Link
Connector
15 Airbag
16 Trunk
17 Heater Ventilation
Air Conditioning
Controller
18 Pre‐Fuse for Fuses
4 and 5