2017 BUICK LACROSSE diagnostic

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
Seats and Restraints 71
prevent the driver from seeing out of
the windshield or being able to steer
the vehicle, nor does it prevent
people from leaving the vehicle.
{Warning
When an airbag inflates, there
may be dust in the air. This dust
could cause breathing problems
for people with a history of
asthma or other breathing trouble.
To avoid this, everyone in the
vehicle should get out as soon as
it is safe to do so. If you have
breathing problems but cannot
get out of the vehicle after an
airbag inflates, then get fresh air
by opening a window or a door.
If you experience breathing
problems following an airbag
deployment, you should seek
medical attention.
The vehicle has a feature that may
automatically unlock the doors, turn
on the interior lamps and hazard
warning flashers, and shut off the
fuel system after the airbags inflate. The feature may also activate,
without airbag inflation, after an
event that exceeds a predetermined
threshold. You can lock the doors,
turn off the interior lamps, and turn
off the hazard warning flashers by
using the controls for those
features.
{Warning
A crash severe enough to inflate
the airbags may have also
damaged important functions in
the vehicle, such as the fuel
system, brake and steering
systems, etc. Even if the vehicle
appears to be drivable after a
moderate crash, there may be
concealed damage that could
make it difficult to safely operate
the vehicle.
Use caution if you should attempt
to restart the engine after a crash
has occurred.
In many crashes severe enough to
inflate the airbag, windshields are
broken by vehicle deformation. Additional windshield breakage may
also occur from the front outboard
passenger airbag.
.
Airbags are designed to inflate
only once. After an airbag
inflates, you will need some new
parts for the airbag system.
If you do not get them, the
airbag system will not be there
to help protect you in another
crash. A new system will include
airbag modules and possibly
other parts. The service manual
for the vehicle covers the need
to replace other parts.
. The vehicle has a crash sensing
and diagnostic module which
records information after a
crash.
See Vehicle Data Recording and
Privacy 0322 andEvent Data
Recorders 0323.
. Let only qualified technicians
work on the airbag systems.
Improper service can mean that
an airbag system will not work
properly. See your dealer for
service.

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
76 Seats and Restraints
Warning (Continued)
seatback may interfere with the
proper operation of the passenger
sensing system.
Servicing the
Airbag-Equipped Vehicle
Airbags affect how the vehicle
should be serviced. There are parts
of the airbag system in several
places around the vehicle. Your
dealer and the service manual have
information about servicing the
vehicle and the airbag system. To
purchase a service manual, see
Service Publications Ordering
Information0320.
{Warning
For up to 10 seconds after the
vehicle is turned off and the
battery is disconnected, an airbag
can still inflate during improper
service. You can be injured if you
(Continued)
Warning (Continued)
are close to an airbag when it
inflates. Avoid yellow connectors.
They are probably part of the
airbag system. Be sure to follow
proper service procedures, and
make sure the person performing
work for you is qualified to do so.
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 any
parts of the front seats, safety belts,
airbag sensing and diagnostic
module, steering wheel, instrument
panel, any of the airbag modules,
ceiling or pillar garnish trim,
overhead console, 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
0 72.

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
Instruments and Controls 113
The front passenger safety belt
reminder light and chime may turn
on if an object is put on the seat
such as a briefcase, handbag,
grocery bag, laptop, or other
electronic device. To turn off the
reminder light and/or chime, remove
the object from the seat or buckle
the safety belt.
Airbag Readiness Light
This light shows if there is an
electrical problem with the airbag
system. 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
0 66.
The airbag readiness light comes on
for several seconds when the
vehicle is started. If the light does
not come on then, have it fixed
immediately.
{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 072. The
overhead console 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. 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 and knee airbag.
If the word ON is lit on the
passenger airbag status indicator, it
means that the front outboard
passenger frontal airbag and knee
airbag are allowed to inflate.
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 and knee
airbag.
If, after several seconds, both status
indicator lights remain on, or if there
are no lights at all, there may be a

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
114 Instruments and Controls
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 0113 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 (Check Engine
Light)
This light is part of the vehicle’s
emission control on-board
diagnostic system. If this light is on
while the engine is running, a
malfunction has been detected and
the vehicle may require service. The
light should come on to show that it
is working when the ignition is in
ON/RUN with the engine not
running for Key Access or in Service
Only Mode for Keyless Access. See
Ignition Positions
0173.
Malfunctions are often indicated by
the system before any problem is
noticeable. Being aware of the light
and seeking service promptly when
it comes on may prevent damage.
Caution
If the vehicle is driven continually
with this light on, the emission
control system may not work as
well, the fuel economy may be
lower, and the vehicle may not
run smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty.

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
Instruments and Controls 115
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not
meet the original tire
specifications, can cause this light
to come on. This could lead to
costly repairs not covered by the
vehicle warranty. This could also
affect the vehicle’s ability to pass
an Emissions Inspection/
Maintenance test. See
Accessories and Modifications
0228.
If the light is flashing : A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service
may be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as
soon as possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle
off and wait at least 10 seconds
before restarting the engine. If the
light is still flashing, follow the
previous guidelines and see your
dealer for service as soon as
possible.
If the light is on steady :
A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
. If fuel has been added to the
vehicle using the capless funnel
adapter, make sure that it has
been removed. See “Filling the
Tank with a Portable Gas Can”
under Filling the Tank 0218.
The diagnostic system can
detect if the adapter has been
left installed in the vehicle,
allowing fuel to evaporate into
the atmosphere. A few driving
trips with the adapter removed
may turn off the light. .
Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed
up. If this occurs, change the
fuel brand. It may require at
least one full tank of the proper
fuel to turn the light off. See Fuel
0 217.
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the
test equipment will likely connect to
the vehicle's Data Link
Connector (DLC).
The DLC is under the instrument
panel to the left of the steering
wheel. Connecting devices that are

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
Driving and Operating 175
engine starts. SeeStarting the
Engine 0175. The ignition will then
remain in ON/RUN.
Service Only Mode
This power mode is available for
service and diagnostics, and Car
Wash Mode. See Automatic
Transmission 0181. Service Only
Mode is also available 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 ENGINE START/STOP 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. Press ENGINE
START/STOP again to turn the
vehicle off.Starting the Engine
Place the transmission in P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral).
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
0 225. To start the vehicle:
1. With the Keyless Access system, the RKE transmitter
must be in the vehicle. Press
ENGINE START/STOP with the
brake pedal applied. When the
engine begins cranking, let go
of the button. The idle speed
will go down as the engine
warms up. Do not race the
engine immediately after
starting it.
If the RKE transmitter is not in
the vehicle, if there is
interference, or if the RKE
battery is low, a Driver
Information Center (DIC)
message will display.
See Key and Lock Messages
0 132 andRemote Keyless
Entry (RKE) System Operation
0 27.

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
190 Driving and Operating
Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak®, an
electronic stability control system.
These systems help limit wheel slip
and assist the driver in maintaining
control, especially on slippery road
conditions.
TCS activates if it senses that any
of the drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak selectively applies
braking pressure to any one of the vehicle wheel brakes to assist the
driver in keeping the vehicle on the
intended path.
If cruise control is being used and
traction control or StabiliTrak begins
to limit wheel spin, cruise control will
disengage. Cruise control may be
turned back on when road
conditions allow.
Both systems come on
automatically when the vehicle is
started and begins to move. The
systems may be heard or felt while
they are operating or while
performing diagnostic checks. This
is normal and does not mean there
is a problem with the vehicle.
It is recommended to leave both
systems on for normal driving
conditions, but it may be necessary
to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow.
See
If the Vehicle Is Stuck 0169
and “Turning the Systems Off and
On” later in this section.
The indicator light for both systems
is in the instrument cluster. This
light will:
.
Flash when TCS is limiting
wheel spin.
. Flash when StabiliTrak is
activated.
. Turn on and stay on when either
system is not working.
If either system fails to turn on or to
activate, a message displays in the
Driver Information Center (DIC),
and
dcomes on and stays on to
indicate that the system is inactive
and is not assisting the driver in
maintaining control. The vehicle is
safe to drive, but driving should be
adjusted accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-9803782) -
2017 - crc - 9/7/16
Vehicle Care 253
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
F1 Left window
F2 Right window
F3 –
F4 HVAC blower
F5 Battery 2 Fuses
Usage
F6 Electric steering column
F7 –
F8 Battery 3
F9 Engine control module/Battery
F10 Body control module 2 On/Off Fuses
Usage
F11 –
F12 –
F13 –
F14 –
F15 Transmission control module On/Off
F16 Amplifier
F17 –
F18 Battery 7
F19 –
F20 Battery 1
F21 Battery 4
F22 Battery 6
F23 Electric steering column lock
F24 Sensing and diagnostic module
F25 Diagnostic link
F26 –
F27 AC DC inverter
F28 –