brake BUICK REGAL 2015 Service Manual

Black plate (31,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
Driving and Operating 9-31
Drive Systems
All-Wheel Drive
If equipped, this feature transfers
torque to the rear wheels as
required. It is fully automatic, and
adjusts itself as needed for road
conditions.
All-Wheel Drive (AWD) performance
is automatically reduced when you
use the compact spare. To restore
full AWD performance, and prevent
excessive wear to the clutch in the
AWD system, replace the compact
spare tire with a full-size tire as
soon as possible. SeeCompact
Spare Tire on page 10-76.
Brakes
Antilock Brake
System (ABS)
This vehicle has ABS, an advanced
electronic braking system that helps
prevent a braking skid.
When 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. See Antilock
Brake System (ABS) Warning Light
on page 5-24. 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 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
you 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

Black plate (32,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
9-32 Driving and Operating
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 may hear the ABS
pump or motor operating and feel
the brake pedal pulsate. This is
normal.
Braking in Emergencies
ABS allows you to steer and brake
at the same time. In many
emergencies, steering can help
more than even the very best
braking.
Parking Brake
The Electric Parking Brake (EPB)
switch is on 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 when the engine
is not running.The system has a red parking brake
status light and an amber parking
brake warning light. See
Electric
Parking Brake Light on page 5-24
and Service Electric Parking Brake
Light on page 5-24. There are also
parking brake-related Driver
Information Center (DIC) messages.
See Brake System Messages on
page 5-39. In case of insufficient
electrical power, the EPB cannot be
applied or released.
Before leaving the vehicle, check
the red parking brake status light to
ensure that the parking brake is
applied.
EPB Apply
To apply the EPB:
1. Be sure the vehicle is at a complete stop.
2. Lift up the EPB switch momentarily.

Black plate (33,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
Driving and Operating 9-33
The red parking brake status light
will flash and then stay on once the
EPB is fully applied. If the red
parking brake status light flashes
continuously, then the EPB is only
partially applied or there is a
problem with the EPB. A DIC
message will display. Release the
EPB and try to apply it again. If the
light does not come on, or keeps
flashing, have the vehicle serviced.
Do not drive the vehicle if the red
parking brake status light is flashing.
See your dealer. SeeElectric
Parking Brake Light on page 5-24.
If the amber parking brake warning
light is on, lift up on the EPB switch
and hold it up. Continue to hold the
switch until the red parking brake
status light remains on. If the amber
parking brake warning light remains
on, see your dealer. If the EPB is applied while the
vehicle is moving, the vehicle will
decelerate as long as the switch is
held up. If the switch is held up until
the vehicle comes to a stop, the
EPB will remain applied.
The vehicle may automatically apply
the EPB in some situations when
the vehicle is not moving. This is
normal, and is done to periodically
check the correct operation of the
EPB system.
If the EPB fails to apply, the rear
wheels should be blocked to
prevent vehicle movement.
EPB Release
To release the EPB:
1. Place the ignition in the ACC/
ACCESSORY or ON/RUN
position.
2. Apply and hold the brake pedal.
3. Push down momentarily on the EPB switch. The EPB is released when the red
parking brake status light is off.
If the amber parking brake warning
light is on, release the EPB by
pushing down on the EPB switch
and holding it down. Continue to
hold the switch until the red parking
brake status light is off. If either light
stays on after release is attempted,
see your dealer.
{Caution
Driving with the parking brake on
can overheat the brake system
and cause premature wear or
damage to brake system parts.
Make sure that the parking brake
is fully released and the brake
warning light is off before driving.

Black plate (34,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
9-34 Driving and Operating
Automatic EPB Release
The EPB will automatically release if
the vehicle is running, placed into
gear, and an attempt is made to
drive away. Avoid rapid acceleration
when the EPB is applied, to
preserve parking brake lining life.
The EPB can also be used to
prevent roll back for vehicles with a
manual transmission taking off on a
hill. When no roll back is desired, an
applied EPB will allow both feet to
be used for the clutch and
accelerator pedals in preparation for
starting the vehicle moving in the
intended direction. In this case,
there is no need to push the switch
to release the EPB.
Brake Assist
The Brake Assist feature is
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)
If equipped, Hill Start Assist (HSA)
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).

Black plate (35,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
Driving and Operating 9-35
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 on
page 9-9 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.

Black plate (36,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
9-36 Driving and Operating
Ifdcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on
and stays on, the vehicle may need
more time to diagnose the problem.
If the condition persists, see your
dealer.
Turning the Systems Off
and On
To turn the system off, press the
TCS/StabiliTrak button on the center
stack.
{Caution
Do not repeatedly brake or
accelerate heavily when TCS is
off. The vehicle driveline could be
damaged.
To turn off only TCS, press and
release the TCS/StabiliTrak
g
button. The traction off lighti
displays in the instrument cluster.
The appropriate message displays
in the DIC. See Ride Control
System Messages on page 5-45.
To turn TCS on again, press and
release the TCS/StabiliTrak
g
button. The traction off lighti
displayed in the instrument cluster
will turn off.
If TCS is limiting wheel spin when
the TCS/StabiliTrak button is
pressed, the system will not turn off
until the wheels stop spinning. To turn off both TCS and
StabiliTrak, press and hold the TCS/
StabiliTrak
gbutton until the
traction off light
iand StabiliTrak
OFF Light
gcome on and stay on
in the instrument cluster. The
appropriate message displays in the
DIC. See Ride Control System
Messages on page 5-45.
To turn TCS and StabiliTrak on
again, press and release the TCS/
StabiliTrak button. The traction off
light
iand StabiliTrak OFF Lightg
in the instrument cluster turn off.
Adding accessories can affect the
vehicle performance. See
Accessories and Modifications on
page 10-3.

Black plate (38,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
9-38 Driving and Operating
Cruise Control
With cruise control the vehicle can
maintain a speed of about 40 km/h
(25 mph) or more without keeping
your foot on the accelerator. Cruise
control does not work at speeds
below 40 km/h (25 mph).
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.If equipped with the Traction Control
System (TCS), the system may
begin to limit wheel spin while you
are using cruise control. If this
happens, the cruise control will
automatically disengage. See
Traction Control/Electronic Stability
Control on page 9-35. If a collision
alert occurs when cruise control is
activated, cruise control is
disengaged. See
Forward Collision
Alert (FCA) System on page 9-52.
When road conditions allow you to
safely use it again, the cruise
control can be turned back on.
If the brakes are applied, the cruise
control disengages.
5(On/Off): Press to turn cruise
control on or off. A white indicator
comes on in the instrument cluster
when cruise is turned on.
RES+ (Resume/Accelerate): If
there is a set speed in memory,
press the control up briefly to
resume to that speed or hold
upwards to accelerate. If cruise
control is already active, use to
increase vehicle speed.

Black plate (39,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
Driving and Operating 9-39
SET−(Set/Coast): Press the
control down briefly to set the speed
and activate cruise control. If cruise
control is already active, use to
decrease vehicle speed.
*(Cancel): Press to disengage
cruise control without erasing the
selected set speed.
Setting Cruise Control
If
5is on when not in use, SET− or
RES+ could get bumped and go into
cruise when not desired. Keep
5
off when cruise is not being used.
1. Press the
5button to turn the
cruise system on.
2. Get up to the speed desired.
3. Press and release the SET− control on the steering wheel.
The desired set speed briefly
appears in the instrument panel
cluster.
4. Remove foot from the accelerator. The cruise control indicator on the
instrument cluster turns green after
cruise control has been set to the
desired speed. See
Instrument
Cluster (Uplevel Cluster) on
page 5-12 orInstrument Cluster
(Base Level Cluster) on page 5-8.
Resuming a Set Speed
If the cruise control is set at a
desired speed and then the brakes
are applied or the
*is pressed, the
cruise control is disengaged without
erasing the set speed from memory.
Once the vehicle reaches about
40 km/h (25 mph) or more, press
RES+ up briefly. The vehicle returns
to the previous set speed.
Increasing Speed While Using
Cruise Control
If the cruise control system is
already activated:
.Press and hold RES+ up until
the desired speed is reached,
then release it.
.To increase vehicle speed in
small increments, press RES+
up briefly. For each press, the
vehicle goes about 1.6 km/h
(1 mph) faster.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster
(Uplevel Cluster) on page 5-12 or
Instrument Cluster (Base Level
Cluster) on page 5-8. The increment
value used depends on the units
displayed.
Reducing Speed While Using
Cruise Control
If the cruise control system is
already activated:
.Press and hold SET− down until
the desired lower speed is
reached, then release it.
.To slow down in small
increments, press SET− down
briefly. For each press, the
vehicle goes about 1.6 km/h
(1 mph) slower.

Black plate (40,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
9-40 Driving and Operating
The speedometer reading can be
displayed in either English or metric
units. SeeInstrument Cluster
(Uplevel Cluster) on page 5-12 or
Instrument Cluster (Base Level
Cluster) on page 5-8. The increment
value used depends on the units
displayed.
Passing Another Vehicle While
Using Cruise Control
Use the accelerator pedal to
increase vehicle speed. When you
take your foot off the pedal, the
vehicle will slow down to the
previous set cruise speed. While
pressing the accelerator pedal or
shortly following the release to
override cruise control, briefly
pressing SET− will result in cruise
set to the current vehicle speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep
hills, you might have to step on the
accelerator pedal to maintain your speed. When going downhill, you
might have to brake or shift to a
lower gear to keep your speed
down. If the brake pedal is applied,
the cruise control will disengage.
Ending Cruise Control
There are four ways to end cruise
control:
.To disengage cruise control,
step lightly on the brake pedal or
clutch.
.Press*on the steering wheel.
.Shift the transmission to
N (Neutral).
.To turn off the cruise control,
press
5on the steering wheel.
Erasing Speed Memory
The cruise control set speed is
erased from memory if
5is pressed
or the ignition is turned off.
Adaptive Cruise Control
If equipped with Adaptive Cruise
Control (ACC), it allows the driver to
select the cruise control set speed
and following gap. Read this entire
section before using this system.
The following gap is the following
time between your vehicle and a
vehicle detected directly ahead in
your path, moving in the same
direction. If no vehicle is detected in
your path, ACC works like regular
cruise control. ACC uses a radar
sensor. See Radio Frequency
Statement on page 13-12.
If a vehicle is detected in your path,
ACC can apply acceleration or
limited, moderate braking to
maintain the selected following gap.
To disengage ACC, apply the brake.
If ACC is controlling your vehicle
speed when the traction control
system (TCS) or electronic stability
control system activates, the ACC
may automatically disengage. See
Traction Control/Electronic Stability
Control on page 9-35. When road

Black plate (41,1)Buick Regal Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
7576024) - 2015 - CRC - 9/15/14
Driving and Operating 9-41
conditions allow ACC to be safely
used, the ACC can be turned
back on.
ACC will not engage if the TCS or
electronic stability control system is
disabled.
{Warning
ACC has limited braking ability
and may not have time to slow
the vehicle down enough to avoid
a collision with another vehicle
you are following. This can occur
when vehicles suddenly slow or
stop ahead, or enter your lane.
Also see“Alerting the Driver” in
this section. Complete attention is
always required while driving and
you should be ready to take
action and apply the brakes. See
Defensive Driving on page 9-3.
{Warning
Adaptive Cruise Control will not
detect or brake for children,
pedestrians, animals, or other
objects.
Do not use Adaptive Cruise
Control when:
.On winding and hilly roads or
when the sensors are
blocked by snow, ice, or dirt.
The system may not detect a
vehicle ahead. Keep the
entire front of the vehicle
clean.
.Visibility is low, such as in
fog, rain, or snow conditions.
Adaptive Cruise Control
performance is limited under
these conditions.
.On slippery roads where fast
changes in tire traction can
cause excessive wheel slip.
](On/Off): Press to turn the
system on or off. The indicator turns
white on the instrument cluster
when ACC is turned on.
RES+ (Resume/Accelerate):
Press the control up briefly to make
the vehicle resume to a previously
set speed, or hold upwards to
accelerate. If cruise control is
already active, use to increase
vehicle speed.