2018 VOLVO XC90 TWIN ENGINE Owners Manual

STARTING AND DRIVING
431
Brake Assist System
The brake enhancing system, Brake Assist
System (BAS

), helps increase braking force and
thereby reduce braking distance. The system monitors the driver's braking habits
and increases braking force when necessary.
Braking force can be increased up to the point at
which the ABS intervenes. The function is deacti-
vated when pressure on the brake pedal is
decreased.
Related information
• Brakes (p. 429) Braking on wet roads
Prolonged driving in heavy rain without braking
may cause braking effect to be slightly delayed
the first time the brakes are applied.
This may also occur after washing the vehicle. It
will then be necessary to apply greater pressure
to the brake pedal. You should therefore maintain
a greater distance to the vehicle ahead.
Firmly apply the brakes after washing the vehicle
or driving on wet roads. This helps warm up the
brake discs, enabling them to dry more quickly
and protecting them against corrosion. Consider
the current traffic situation when braking.
Related information
• Brakes (p. 429)
• Braking on salted roads (p. 431) Braking on salted roads
When driving on salted roads, a layer of salt may
form on the brake discs and brake pads.
This could increase stopping distance. Maintain
an extra large safety distance to the vehicle
ahead. Make sure to also:
• Apply the brakes from time to time to help
remove salt. Make sure braking does not
pose a risk to any other road users.
• Gently apply the brakes when you have fin-
ished driving and before driving again.
Related information
•Brakes (p. 429)
• Braking on wet roads (p. 431)

STARTING AND DRIVING
432Maintenance of the brake system
Regularly check the brake system components
for wear. To keep the vehicle as safe and reliable as possi-
ble, follow the Volvo service schedule specified in
the Warranty and Maintenance Records Informa-
tion booklet. New and replaced brake pads and
brake discs do not provide optimal braking effect
until they are "broken in" by driving a few hun-
dred kilometers (miles). Compensate for the
reduced braking effect by applying greater pres-
sure to the brake pedal. Volvo recommends only
using brake pads approved for your Volvo.
CAUTION The brake system's components should be
regularly checked for wear.
Contact a workshop for advice on how to do
this or let a workshop perform the inspection
- an authorized Volvo workshop is recom-
mended.
Related information
•
Brakes (p. 429) Parking brake
The parking brake helps keep the vehicle sta-
tionary by mechanically locking two wheels.
The parking brake controls are located in the tunnel
console between the seats.
When the electric parking brake is being applied,
a faint sound can be heard from the brake's elec-
tric motor. This sound can also be heard during
the automatic function check of the parking
brake.
If the vehicle is stationary when the parking brake
is applied, it will only be applied to the rear
wheels. If it is applied while the vehicle is moving,
the normal brakes will be used on all four wheels.
Braking will be transferred to only the rear
wheels when the vehicle is almost stopped.
Related information
• Activating and deactivating the parking brake
(p. 433)
• Parking on a hill (p. 434)
• Parking brake malfunction (p. 435)
• Auto-hold brakes (p. 436)

STARTING AND DRIVING
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433
Activating and deactivating the
parking brake
Use the parking brake to help keep the vehicle
stationary when it is parked.
Activating the parking brake
1. Pull up the control.
>
The symbol in the instrument panel will
illuminate when the parking brake is acti-
vated.
2. Make sure the vehicle is stationary.
Symbol in the instrument panel Symbol
Meaning A
B
The symbol will be illuminated
when the parking brake is acti-
vated.
A flashing symbol indicates that a
fault has been detected. Read the
message in the instrument panel. A
Canadian models.
B US models.
Automatic activation
The parking brake is applied automatically:
• if the Auto-hold function (automatic brake
application when the vehicle is stationary) is
activated and the vehicle has been stationary
for a prolonged period of time (5-10
minutes).
• when the gear selector is moved to P on a
steep hill.
• when the ignition is switched off and the set-
ting for automatically activating the parking
brake is activated in the center display.
Emergency braking
In an emergency, the parking brake can be acti-
vated when the vehicle is moving by pulling and holding up the control. The braking process is
canceled when the control is released or if the
accelerator pedal is depressed.
NOTE In case of emergency braking at high speeds,
a signal sounds during the brake procedure.
Deactivating the parking brake
Deactivating manually
1. Depress the brake pedal firmly.
2. Press the control.
> The parking brake will release and thesymbol in the instrument panel will go out.

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434
Deactivating automatically
1. Fasten your seat belt.
2. Depress the brake pedal firmly.
3. Start the vehicle.
4.
Move the gear selector to D or R and press
the accelerator pedal.
> The parking brake will release and the symbol in the instrument panel will go out.
NOTE When the vehicle is initially started, the park-
ing brake could disengage automatically even
if the driver's seat belt is not buckled.
Related information
•
Settings for automatically activating the park-
ing brake (p. 434)
• Parking brake malfunction (p. 435)
• Parking brake (p. 432)
• Parking on a hill (p. 434) Settings for automatically activating
the parking brake
Choose whether the parking brake should be
activated automatically when the vehicle is
switched off.
This selection is made in the Settings menu in
the center display.
1. Tap Settings in the Top view.
2.

Tap My Car Parking Brake and
Suspension and select or deselect the
Auto Activate Parking Brake function.
Related information
• Activating and deactivating the parking brake
(p. 433)
• Parking brake (p. 432) Parking on a hill
Always use the parking brake when parking on a
hill.
WARNING Always apply the parking brake when parking
on an incline. Selecting a gear or putting the
automatic transmission in P may not be suffi-
cient to keep the vehicle stationary in all sit-
uations.
If the vehicle is pointing uphill: • Turn the front wheels so they are pointing
away from the curb.
If the vehicle is pointing downhill:
• Turn the front wheels so they are pointing
toward the curb.
Heavy load uphill
Heavy loads, such as a trailer, could cause the
vehicle to roll backward when the parking brake
is released automatically on steep uphill gradi-
ents. To help avoid this, pull the control upward
while you are driving away. Release the control
when the vehicle gains traction.
Related information
• Activating and deactivating the parking brake
(p. 433)

STARTING AND DRIVING
435
Parking brake malfunction
If you are unable to deactivate or activate the
parking brake after several attempts, contact an
authorized Volvo workshop.
A audible warning signal will sound if the parking
brake is applied while the vehicle is being driven.
If the vehicle must be parked before the problem
is rectified, turn the wheels as when parking on
an incline and put the gear selector in P.
Low battery charge levelIf the battery charge level is too low, it will not be
possible to apply or release the parking brake.
Connect an auxiliary battery to the vehicle if the
battery is discharged.
Replacing brake padsDue to the design of the electric parking brake,
the rear brake pads must be replaced by a work-
shop. An authorized Volvo workshop is recom-
mended.
Symbols in the instrument panel Symbol
Meaning A
B
A flashing symbol indicates that a
fault has been detected. See the
message in the instrument panel. A
B
Fault in the brake system. See the
message in the instrument panel. Information message in the instru-
ment panel.
A
Canadian models.
B US models.Related information
• Activating and deactivating the parking brake
(p. 433)
• Start battery (p. 615)
• Volvo's service program (p. 598)

STARTING AND DRIVING
436Auto-hold brakes
With the Auto-hold brake function, the driver can
release the brake pedal and the brakes will
remain applied, for example, when the vehicle
has stopped at a traffic light or intersection.
When the vehicle stops, the brakes are activated
automatically. The function can use either the
normal brakes or the parking brakes to keep the
vehicle stationary and works on flat surfaces or
hills. When driving off, the brakes will be automat-
ically released if the driver's seat belt is buckled.
NOTE When braking to a stop on an uphill or down-
hill gradient, depress the brake pedal with
slightly more force than usual before releas-
ing to ensure that the vehicle cannot move at
all.
The parking brake is activated if:
•
the vehicle is switched off
• the driver's door is opened
• the driver's seat belt is removed
• the vehicle has been stationary for a pro-
longed period of time (5-10 minutes)
Symbols in the instrument panel Symbol
Meaning This symbol illuminates when the
function is using the normal brakes
to keep the vehicle stationary.
A
B
This symbol illuminates when the
function is using the parking brake
to keep the vehicle stationary. A
Canadian models.
B US models.
Related information
• Activating and deactivating Auto-hold at a
standstill (p. 436)
• Brakes (p. 429)
• Parking brake (p. 432)
• Hill Start Assist (p. 437) Activating and deactivating Auto-
hold at a standstill
The Auto-hold brake function at a standstill is
activated with the button in the tunnel console.
–
Press the button in the tunnel console to
activate or deactivate the function.
>

The indicator light in the button will illumi-
nate when the function is activated. The
function will remain active the next time
the vehicle is started.

STARTING AND DRIVING
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437
When shutting offIf the function is active and holding the
vehicle stationary using the normal
brakes (A symbol lit), the brake pedal
must be depressed while pressing the
button in order to deactivate Auto-hold. •
The function will remain off until it is reactiva-
ted.
• When Auto-hold is switched off, Hill Start
Assist (HSA) will remain active to help pre-
vent the vehicle from rolling backward when
starting up a hill.
Related information
•Auto-hold brakes (p. 436) Hill Start Assist
The function for assisting when starting the vehi-
cle on inclines, Hill Start Assist (HSA), helps
prevent the vehicle from rolling backward when
starting on an uphill gradient. When backing up
a hill, HSA helps prevent the vehicle from rolling
forward.
The function retains pressure from the brake
pedal in the brake system for several seconds
after the brake pedal has been released.
This temporary braking effect is released after a
few seconds or when the driver begins driving.
Hill Start Assist is available even if the Auto-hold
brake function is switched off.
Related information
• Auto-hold brakes (p. 436)
• Brakes (p. 429) Braking assist after a collision
In a collision in which the activation level is
reached for the pyrotechnic seat belt tensioners
or airbags, or if a collision with a large animal is
detected, the vehicle's brakes will be automati-
cally activated. This function is intended to help
prevent or reduce the effects of any subsequent
collision.
After a serious collision, it may no longer be pos-
sible to control and steer the vehicle. In order to
avoid or mitigate a possible further collision with
a vehicle or an object in the vehicle's path, the
brake assist system is activated automatically to
help stop the vehicle safely.
The brake lights and hazard warning flashers are
activated during braking. When the vehicle has
stopped, the hazard warning flashers will con-
tinue to flash and the parking brake will be
applied.
If braking is not appropriate, e.g. if there is a risk
of being hit by passing traffic, the driver can over-
ride the system by depressing the accelerator
pedal.
This function assumes that the brake system is
intact after a collision.
Brake assist is part of the Rear Collision Warning
and Blind Spot Information safety systems.

||STARTING AND DRIVING
* Option/accessory.
438
Related information
• Rear Collision Warning (p. 347)
• BLIS* (p. 348)
• Brake functions (p. 429) Transmission
The transmission is part of the vehicle's driveline
(power transmission) between the engine and
the drive wheels. The function of the transmis-
sion is to change gears depending on speed
and power needs.
The vehicle has an 8-speed automatic transmis-
sion and an electric motor for rear-wheel drive.
The number of gears allows the engine's torque
and power band to be effectively utilized. Two of
the gears are overdrive gears that save fuel when
driving at a constant engine speed. The steering
wheel paddles* can be used to shift up or down
manually. The instrument panel shows the gear
currently in use.
CAUTION Check the operating temperature of the
transmission to help avoid damage to any of
the drive system components. If there is a risk
of overheating, a warning symbol will appear
in the instrument panel and a text message
will be displayed. Follow the recommenda-
tions given.
Symbols in the instrument panelIf a problem should occur with the transmission, a
symbol and a message will appear in the instru-
ment panel. Symbol
Meaning Information and messages related
to the transmission. Follow the rec-
ommendations provided.
Hot or overheated transmission.
Follow the recommendations provi-
ded.
Reduced performance/Acceler-
ation performance reduced
In the event of a temporary fault in
the driveline, the vehicle may go
into a "limp home" mode with
reduced power output to help avoid
damage to the driveline.
Related information
• Gear selector positions for automatic trans-
missions (p. 439)
• Gear indicator* (p. 442)