light BUICK LACROSSE 2015 Owner's Manual

Black plate (21,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Vehicle Care 10-21
The coolant surge tank pressure
cap can be removed when the
cooling system, including the surge
tank pressure cap and upper
radiator hose, is no longer hot.
1. Turn the pressure cap slowlycounterclockwise. If a hiss is
heard, wait for that to stop.
A hiss means there is still some
pressure left.
2. Keep turning the cap and remove it.
3. Fill the coolant surge tank withthe proper mixture to the mark
pointed to on the front of the
coolant surge tank.
4. With the coolant surge tank cap off, start the engine and let it run
until the upper radiator hose
starts getting hot. Watch out for
the engine cooling fans. By this
time, the coolant level inside the
coolant surge tank may be
lower. If the level is lower, add
more of the proper mixture to the
coolant surge tank until the level reaches the mark pointed to on
the front of the coolant
surge tank.
5. Replace the cap tightly.
{Caution
If the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
There is a coolant temperature
gauge and a engine coolant
temperature warning light on the
instrument cluster that indicate an
overheated engine condition. See
Engine Coolant Temperature Gauge
on page 5-13 andEngine Coolant
Temperature Warning Light on
page 5-22.

Black plate (22,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
10-22 Vehicle Care
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program on
page 13-5.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, the fans
should be running. If not, do not
continue to run the engine and have
the vehicle serviced.
{Caution
Running the engine without
coolant may cause damage or a
fire. Vehicle damage would not be
covered by the vehicle warranty.
If Steam Is Coming from the
Engine Compartment
SeeOverheated Engine Protection
Operating Mode on page 10-23 for
information on driving to a safe
place in an emergency.
If No Steam Is Coming from
the Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen
or heard, the problem might not be
too serious. Sometimes the engine
can get a little too hot when the
vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
.Tows a trailer. If the overheat warning displays with
no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest
temperature and to the highest
fan speed. Open the windows as
necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral), and let the
engine idle.
If the temperature overheat gauge is
no longer in the overheat zone or an
engine coolant temperature warning
light no longer displays, the vehicle
can be driven. Continue to drive the
vehicle slowly for about 10 minutes.
Keep a safe vehicle distance from
the vehicle in front. If the warning
does not come back on, continue to
drive normally and have the cooling
system checked for proper fill and
function.

Black plate (23,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Vehicle Care 10-23
If the warning continues, pull over,
stop, and park the vehicle
right away.
If there is no sign of steam, idle the
engine for three minutes while
parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, seeOverheated
Engine Protection Operating Mode
on page 10-23.
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. 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 and 3.6L
V6 Engine with FWD)
The vehicle has electric power
steering and does not use power
steering fluid.
Power Steering Fluid
(3.6L V6 Engine
with AWD)
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 (25,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Vehicle Care 10-25
{Caution
.Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system
and paint.
.Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
to freeze and damage the
washer fluid tank and other
parts of the washer system.
.When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
.Fill the washer fluid tank only
three-quarters full when it is
very cold. This allows for fluid
expansion if freezing occurs,
which could damage the tank
if it is completely full.
Brakes
Disc brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time when the vehicle
is moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
{Caution
Continuing to drive with worn-out
brake pads could result in costly
brake repair.Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications. See
Capacities and
Specifications on page 12-2.
Brake pads should be replaced as
complete sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service may be required.

Black plate (26,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
10-26 Vehicle Care
Replacing Brake System Parts
Always replace brake system parts
with new, approved replacement
parts. If this is not done, the brakes
may not work properly. The braking
performance expected can change
in many other ways if the wrong
replacement brake parts are
installed or parts are improperly
installed.
Brake Fluid
The brake master cylinder reservoir
is filled with DOT 3 brake fluid as
indicated on the reservoir cap. See
Engine Compartment Overview on
page 10-6for the location of the
reservoir. There are only two reasons why the
brake fluid level in the reservoir
might go down:
.The brake fluid level goes down
because of normal brake lining
wear. When new linings are
installed, the fluid level goes
back up.
.A fluid leak in the brake
hydraulic system can also cause
a low fluid level. Have the brake
hydraulic system fixed, since a
leak means that sooner or later
the brakes will not work well.
Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings are
worn, there will be too much fluid
when new brake linings are
installed. Add or remove brake fluid,
as necessary, only when work is
done on the brake hydraulic system.
{Warning
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light on page 5-19.
What to Add
Use only new DOT 3 brake fluid
from a sealed container. See
Recommended Fluids and
Lubricants on page 11-12.
Always clean the brake fluid
reservoir cap and the area around
the cap before removing it. This
helps keep dirt from entering the
reservoir.

Black plate (31,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Vehicle Care 10-31
Headlamp Aiming
Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.
Bulb Replacement
For the proper type of replacement
bulbs, seeReplacement Bulbs on
page 10-34.
For any bulb changing procedure
not listed in this section, contact
your dealer.
Halogen Bulbs
{Warning
Halogen bulbs have pressurized
gas inside and can burst if you
drop or scratch the bulb. You or
others could be injured. Be sure
to read and follow the instructions
on the bulb package.
High Intensity Discharge
(HID) Lighting
{Warning
The high intensity discharge
lighting system operates at a very
high voltage. If you try to service
any of the system components,
you could be seriously injured.
Have your dealer or a qualified
technician service them.
After an HID headlamp bulb has
been replaced, the beam might be a
slightly different shade than it was
originally. This is normal.
LED Lighting
This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer.

Black plate (32,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
10-32 Vehicle Care
Headlamps, Front Turn
Signal and Parking
Lamps
Base Headlamp Assembly
The base model vehicle has a
halogen high/low-beam headlamp,
parking lamp, and a turn signal lamp
on the headlamp assembly.
For replacement of the turn signal
lamp bulb on an eAssist vehicle,
contact your dealer.
1. Headlamp
2. Turn Signal Lamp
To replace one of these bulbs:
1. Open the hood. SeeHood on
page 10-5.
2. If replacing a headlamp bulb, remove the dust cover from the
back of the headlamp housing
by turning counterclockwise
one-quarter turn.
3. If replacing a turn signal lamp bulb on a non-eAssist vehicle,
remove the close out panel push
pins and close out panel
covering the bulb socket.
4. Remove the bulb socket from the headlamp by turning
counterclockwise
one-quarter turn.
5. Remove the bulb from the socket. If replacing the high/
low-beam bulb, pry the two clips
on either end of the bulb and pull
straight out.
6. Reverse Steps 1–5 to install.Uplevel Headlamp Assembly
The uplevel model vehicle has a
high intensity discharge (HID) high/
low beam, DRL/parking lamp, and a
turn signal lamp on the headlamp
assembly. See High Intensity
Discharge (HID) Lighting on
page 10-31.
To replace one of these bulbs:
1. Open the hood. See Hood on
page 10-5.
2. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly.

Black plate (38,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
10-38 Vehicle Care
Mini Fuses Usage14 Cabin Heater Coolant Pump
(eAssist)/Secondary
Air Injector/
Secondary Air
Injector with
Pressure Sensor
15 Motor Generator Unit Coolant Pump
(eAssist)
16 Run/Crank for eAssist Power
Inverter Module
17 Not Used
18 Sunshade Module, Vehicle Air
Purification System,
Ventilated Seats
20 Heated Steering Wheel (non eAssist) Mini Fuses Usage
23 Variable Effort Steering (if
equipped) or eAssist
Power Inverter
Module
29 Heated Seat, Left/ Power Lumbar
30 Heated Seat, Right/ Power Pack Cooling
Fan (eAssist)
31 All-Wheel Drive, Electronic
Suspension Control
32 Body Control Module 6
33 Memory Seat –
Front
34 Antilock Brake System Valves
35 Amplifier
36 Adaptive Forward Lighting (AFL)
Motors–Battery Mini Fuses Usage
37 Right High Beam
38 Left High Beam
46 Cooling Fan Relay
47 Six Cylinder Engine: Pre Catalytic
Converter Oxygen
Sensor Heater,
Canister Purge
Solenoid. Four
Cylinder Engine: Pre
and Post Catalytic
Converter Oxygen
Sensor Heaters,
Canister Purge
Solenoid
48 Fog Lamps
49 Right High Intensity Discharge
Headlamp
50 Left High Intensity Discharge
Headlamp
51 Horn

Black plate (39,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
Vehicle Care 10-39
Mini Fuses Usage52 Cluster Run/Crank
53 Run/Crank for Inside Rearview Mirror,
Rear Vision Camera,
Air Quality Sensor,
Aero Shutter Motor
54 Run/Crank for: Heating, Ventilation
and Air
Conditioning,
Headlamp Switch
55 Outside Rearview Mirror, Universal
Remote System,
Front Window
Switches
56 Windshield Washer
60 Heated Mirror
62 Canister Vent
64 Adaptive Forward Lighting (AFL)
Module–Battery
65 Not Used Mini Fuses Usage
66 AIR Solenoid (eAssist)
67 Fuel Pump Power Module/Chassis
Control Module
69 Regulated Voltage Control Sensor
70 Parking Assist/Side Blind Zone
71 Passive Entry/ Passive Start
Mini Relays Usage 7 Engine Control Module
9 Cooling Fan
13 Cooling Fan
15 Run/Crank
16 AIR Pump
17 Rear Window Defogger Micro
Relays Usage
1 Air Conditioning Compressor Clutch
2 Starter
4 Wiper Speed
5 Wiper Control
6 Cabin Heater Coolant Pump
(eAssist)/Secondary
Air Injector/
Secondary Air
Injector with
Pressure Sensor
10 Cooling Fan
14 Headlamp Low Beam
Ultra Micro Relays Usage
11 Transmission Auxiliary Oil Pump
(eAssist)

Black plate (40,1)Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7707475) - 2015 - CRC - 10/9/14
10-40 Vehicle Care
Instrument Panel Fuse
Block
The instrument panel fuse block is
located in the instrument panel, on
the driver side of the vehicle. To
access the fuses, open the fuse
panel door by pulling down at
the top.
Press in on the sides of the door to
release it from the instrument panel.
Pull the door toward you to release
it from the hinge.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
1 APO 3
2 Body Control Module 7
3 Steering Wheel Controls Backlight
4 Radio/Human Machine Interface/
Rear Auxiliary Audio
Jack/Front Auxiliary
Audio Video Jack/
Touchpad/Remote
Media Player/
Blu–ray Remote
Media Player
5 OnStar/Universal Hands–Free Phone
6 Power Outlet 1
7 Power Outlet 2
8 Body Control Module 1