brakes CHEVROLET IMPALA 2018 User Guide

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
178 Driving and Operating
Brakes
Antilock Brake
System (ABS)
This vehicle has an Antilock Brake
System (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
may be heard while this test is going
on, and it may 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. SeeAntilock
Brake System (ABS) Warning Light
0 121. 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
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.
Electric Parking Brake

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
180 Driving and Operating
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.
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.
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 underconditions 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)
Some vehicles have a Hill Start
Assist (HSA) feature, which may be
useful when the vehicle is stopped
on a grade. This feature is designed
to temporarily prevent the vehicle
from rolling, either forward or
rearward, during vehicle drive off.
After the driver completely stops
and holds the vehicle in a completestandstill 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 within a two-second window
of releasing the brake pedal, and
the vehicle may begin to roll. 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).
HSA will activate on stop/start
vehicles while in gear and facing
down hill to assist in allowing a
smooth auto start.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
Driving and Operating 181
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 thevehicle wheel brakes to assist the
driver in keeping the vehicle on the
intended path.
If cruise control is being used and
TCS 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 0163
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.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
Driving and Operating 183
automatically disengage. See
Traction Control/Electronic Stability
Control0181. If a collision alert
occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System 0195. 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: Press to turn cruise control on
or off. A white indicator comes on in
the instrument cluster when cruise
is on.
+RES : If there is a set speed in
memory, press briefly to resume to
that speed or press and hold to
accelerate. If cruise control is
already active, use to increase
vehicle speed.
SET– :Press briefly to set the
speed and activate cruise control.
If cruise control is already active,
use to decrease vehicle speed.
*: 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 pressed and go into
cruise when not desired. Keep
5
off when cruise is not being used.
1. Press
5to turn the cruise
control system on.
2. Get up to the desired speed. 3. Press and release SET–
.
4. Remove foot from the accelerator.
The cruise control indicator on the
instrument cluster turns green after
the cruise control has been set to
the desired speed. See Instrument
Cluster 0110.
Resuming a Set Speed
If the cruise control is set at a
desired speed and then the brakes
are applied or
*is pressed, the
cruise control is disengaged without
erasing the set speed from memory.
Once the vehicle speed is 40 km/h
(25 mph) or greater, briefly press
+RES. 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 until the
desired speed is reached, then
release it.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
Driving and Operating 185
direction. If no vehicle is detected in
your path, ACC works like regular
cruise control. ACC uses a radar
sensor. SeeRadio Frequency
Statement 0317.
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 StabiliTrak System
activates, the ACC may
automatically disengage. When road
conditions allow ACC to be safely
used, the ACC can be turned back
on. If TCS or StabiliTrak have been
disabled, the ACC will not engage.
See Traction Control/Electronic
Stability Control 0181.
{Warning
ACC has limited braking ability
and may not have time to slow
the vehicle down enough to avoid
a collision with another vehicle
(Continued)
Warning (Continued)
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 0158.
{Warning
ACC will not detect or brake for
children, pedestrians, animals,
or other objects.
Do not use ACC 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.
(Continued)
Warning (Continued)
.Visibility is low, such as in
fog, rain, or snow
conditions. ACC
performance is limited under
these conditions.
. On slippery roads where
fast changes in tire traction
can cause excessive
wheel slip.
]:Press to turn the system on or
off. A white Adaptive Cruise Control
indicator comes on.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
186 Driving and Operating
+RES :Press briefly to resume the
previous set speed or hold to
accelerate. If ACC is already active,
use to increase vehicle speed.
SET– :Press briefly to set the
speed and activate ACC. If ACC is
already active, use to decrease
vehicle speed.
*: Press to disengage ACC
without erasing the selected set
speed.
GAP : Press to select a following
gap time (or distance) setting for
ACC of Far, Medium, or Near.
Setting Adaptive Cruise Control
If the cruise system is on but not in
use, it could get set and go into
cruise when not desired. Keep the
cruise control button off when cruise
is not being used.
Select the set speed desired for
cruise. This is the vehicle speed
when no vehicle is detected in
its path.
ACC will not set or resume at a
speed less than 25 km/h (16 mph). To set ACC:
1. Press
].
2. Get up to the desired speed.
3. Press and release SET–.
4. Remove foot from the accelerator.
After ACC is set, it may immediately
apply the brakes if a vehicle ahead
is closer than the selected
following gap.
The ACC indicator displays on the
instrument cluster. When ACC is
active, the indicator turns green.
Be mindful of speed limits,
surrounding traffic speeds, and
weather conditions when selecting
the set speed. Resuming a Set Speed
If the ACC is set at a desired speed
and then the brakes are applied,
ACC is disengaged without erasing
the set speed from memory.
To begin using ACC again, press
+RES. The vehicle returns to the
previous set speed.
Increasing Speed While ACC is at
a Set Speed
If ACC is already activated, do one
of the following:
.
Use the accelerator to get to the
higher speed. Press SET–.
Release the control and the
accelerator pedal. The vehicle
will now cruise at the higher
speed.
When the accelerator pedal is
pressed, ACC will not brake
because it is overridden.
A warning message will appear
on the Driver Information Center
(DIC). See Vehicle Messages
0 127.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
188 Driving and Operating
Alerting the Driver
If ACC is engaged, driver action
may be required when ACC cannot
apply sufficient braking because of
approaching a vehicle too rapidly.
When this condition occurs, six red
lights will flash on the windshield
and eight beeps will sound from the
front.
SeeDefensive Driving 0158.
Approaching and Following a
Vehicle
The vehicle ahead symbol is in
the DIC. The vehicle ahead symbol only
displays when a vehicle is detected
in your vehicle’s path moving in the
same direction.
If this symbol is not displaying, ACC
will not respond to or brake to
vehicles ahead.
ACC automatically slows the vehicle
down and adjusts vehicle speed to
follow the vehicle in front at the
selected follow gap. The vehicle
speed increases or decreases to
follow the vehicle in front of you, but
will not exceed the set speed. It may
apply limited braking, if necessary.
When braking is active, the brake
lights will come on. The automatic
braking may feel or sound different
than if the brakes were applied
manually. This is normal.
Stationary or Very Slow-Moving
Objects
{Warning
ACC may not detect and react to
stopped or slow-moving vehicles
ahead of you. For example, the
system may not brake for a
vehicle it has never detected
moving. This can occur in
stop-and-go traffic or when a
vehicle suddenly appears due to
a vehicle ahead changing lanes.
Your vehicle may not stop and
could cause a crash. Use caution
when using ACC. Your complete
attention is always required while
driving and you should be ready
to take action and apply the
brakes.
ACC Automatically Disengages
ACC may automatically disengage
and the driver will need to manually
apply the brakes to slow the
vehicle if:
. The sensors are blocked.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
Driving and Operating 189
.The Traction Control System
(TCS) or electronic stability
control system has activated or
been disabled.
. There is a fault in the system.
. The radar falsely reports
blockage when driving in a
desert or remote area with no
other vehicles or roadside
objects. A DIC message may
display to indicate that ACC is
temporarily unavailable.
A message indicating that the cruise
is disengaging will appear on the
DIC and the ACC active symbol will
not be displayed when ACC is no
longer active.
Notification to Resume ACC
ACC will maintain a following gap
behind a detected vehicle and slow
your vehicle to a stop behind that
vehicle.
If the stopped vehicle ahead has
driven away and ACC has not been
resumed, the vehicle ahead symbol
will flash as a reminder to check
traffic ahead before proceeding. In addition, three beeps will sound.
See
“Go Notifier” under Collision/
Detection systems in Vehicle
Personalization 0128.
When the vehicle ahead drives
away, press +RES or the
accelerator pedal to resume cruise
control. If stopped for more than
two minutes or if the driver door is
opened, the ACC automatically
applies the Electric Parking Brake
(EPB) to hold the vehicle. The EPB
status light will turn on. See Electric
Parking Brake 0178. To resume
ACC and release the EPB, press
the accelerator pedal. ACC can be
resumed when the vehicle is
travelling greater than 25 km/h
(16 mph).
A DIC warning message may
display indicating to shift to P (Park)
before exiting the vehicle. See
Vehicle Messages 0127.{Warning
If ACC has stopped the vehicle,
and if ACC is disengaged, turned
off, or canceled, the vehicle will
no longer be held at a stop. The
vehicle can move. When ACC is
holding the vehicle at a stop,
always be prepared to manually
apply the brakes.
{Warning
Leaving the vehicle without
placing it in P (Park) can be
dangerous. Do not leave the
vehicle while it is being held at a
stop by ACC. Always place the
vehicle in P (Park) and turn off
the ignition before leaving the
vehicle.
ACC Override
If using the accelerator pedal while
ACC is active, a DIC warning
message will indicate that automatic

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
190 Driving and Operating
braking will not occur. SeeVehicle
Messages 0127. ACC will resume
operation when the accelerator
pedal is not being pressed.
{Warning
The ACC will not automatically
apply the brakes if your foot is
resting on the accelerator pedal.
You could crash into a vehicle
ahead of you.
Curves in the Road
{Warning
On curves, ACC may not detect a
vehicle ahead in your lane. You
could be startled if the vehicle
accelerates up to the set speed,
especially when following a
vehicle exiting or entering exit
ramps. You could lose control of
the vehicle or crash. Do not use
ACC while driving on an entrance
or exit ramp. Always be ready to
use the brakes if necessary.
{Warning
On curves, ACC may respond to
a vehicle in another lane, or may
not have time to react to a vehicle
in your lane. You could crash into
a vehicle ahead of you, or lose
control of your vehicle. Give extra
attention in curves and be ready
to use the brakes if necessary.
Select an appropriate speed while
driving in curves.
ACC may operate differently in a
sharp curve. It may reduce the
vehicle speed if the curve is too
sharp.
When following a vehicle and
entering a curve, ACC may not
detect the vehicle ahead and
accelerate to the set speed. When
this happens, the vehicle ahead
symbol will not appear.
ACC may detect a vehicle that is
not in your lane and apply the
brakes.
ACC may occasionally provide an
alert and/or braking that is
considered unnecessary. It could
respond to vehicles in different
lanes, signs, guardrails, and other
stationary objects when entering or
exiting a curve. This is normal
operation. The vehicle does not
need service.

Chevrolet Impala Owner Manual (GMNA-Localizing-U.S./Canada-11348316) -
2018 - CRC - 8/22/17
Driving and Operating 191
Other Vehicle Lane Changes
ACC will not detect a vehicle ahead
until it is completely in the lane. The
brakes may need to be manually
applied.
Do Not Use ACC on Hills and
When Towing a Trailer
Do not use ACC when driving on
steep hills or when towing a trailer.
ACC will not detect a vehicle in the
lane while driving on steep hills. The
driver will often need to take over
acceleration and braking on steep
hills, especially when towing a
trailer. If the brakes are applied, the
ACC disengages.
Disengaging ACC
There are three ways to
disengage ACC:
.Step lightly on the brake pedal.
. Press
*.
. Press
].
Erasing Speed Memory
The cruise control set speed is
erased from memory if
]is
pressed or if the ignition is
turned off. Cleaning the Sensing System
The radar sensor on the front of the
vehicle can become blocked by
snow, ice, dirt, or mud. These areas
need to be cleaned for ACC to
operate properly.
For cleaning instructions, see
“Washing the Vehicle”
under
Exterior Care 0281.
System operation may also be
limited under snow, heavy rain,
or road spray conditions.