2011 VOLVO XC70 wheel

04 Comfort and driving pleasure
Stability system
04

157 Introduction
The Dynamic Stability and Traction Control
system (DSTC) consists of a number of func-
tions designed help reduce wheel spin, coun-
teract skidding, and to generally help improve
directional stability.
CAUTION
A pulsating sound will be audible when the
system is actively operating and is normal.
Traction control (TC)This function is designed to help reduce wheel
spin by transferring power from a drive wheel
that begins to lose traction to the wheel on the
opposite side of the vehicle (on the same axle).
TC is most active at low speeds.
This is one of DSTC's permanent functions and
cannot be switched off.
Active Yaw Control (AYC)This function helps maintain directional stabil-
ity, for example when cornering, by braking
one or more of the wheels if the vehicle shows
a tendency to skid or slide laterally.
This is one of DSTC's permanent functions and
cannot be switched off.
Spin control (SC)The spin control function is designed to help
prevent the drive wheels from spinning while
the vehicle is accelerating.
Under certain circumstances, such as when
driving with snow chains, or driving in deep
snow or loose sand, it may be advisable to
temporarily switch off this function for maxi-
mum tractive force.
WARNING
The car's handling and stability characteris-
tics will be altered if the spin control function
has been disabled.
Operation
G021409
Temporarily switching off Spin control1.
Turn the thumbwheel (1) until the DSTC
menu is shown.
2.
Hold down the RESET button (2) to toggle
between
DSTC SPIN CONTROL ON/
OFF.
Symbols in the instrument panel
If the symbols and are displayed
at the same time, read the message in the
information display.
If the symbol
appears alone, it may
appear as follows:
•If the symbol flashes, this indicates that the
stability system is actively functioning to
help counteract wheel spin and/or a skid.
•If the symbol remains on for approximately
2 seconds after the engine has been
started, this indicates that the system is
performing a self-diagnostic test.
WARNING
The stability system is intended to help
improve driving safety. It supplements, but
can never replace, the driver's judgment
and responsibility when operating the vehi-
cle. Speed and driving style should always
be adapted to traffic and road conditions.

04 Comfort and driving pleasure
Stability system
04
158
Messages in the information display
DSTC Temporarily OFF – system function
has been temporarily reduced due to high
brake disc temperature. The function is acti-
vated automatically when the brakes have
cooled.
DSTC Service required – the system has
been disabled due to a fault. If this occurs:
1. Stop the vehicle in a safe place and turn off
the engine.
2. Restart the engine.
If the message remains when the engine is
restarted, drive to an authorized Volvo work-
shop to have the system inspected.
Symbols in the instrument panel
If the symbols and are displayed
at the same time, read the message in the
information display.
If the symbol
appears alone, it may
appear as follows:
•If the symbol flashes, this indicates that the
stability system is actively functioning to
help counteract wheel spin and/or a skid.
•If the symbol remains on for approximately
2 seconds after the engine has been
started, this indicates that the system is
performing a self-diagnostic test.

04 Comfort and driving pleasure
Cruise control
04
160
Operation
G022910
Steering wheel-mounted controls and display
Standby mode
Resume set speed
Deactivating
Activate/set speed
Set speed indicator (parentheses indicate
standby mode)
Engaging the cruise control functionBefore a speed can be set, the cruise control
system must be engaged (put in standby
mode).

Press the CRUISE button (1).>
The symbol
illuminates and the text
(---) mph (5) indicates that cruise con-
trol is in standby mode.
NOTE
This does not set the vehicle's speed.
Setting a speed
Use the or buttons set the vehicle's cur-
rent speed. The set speed is shown in the dis-
play.
NOTE
Cruise control cannot be engaged at
speeds below 20 mph (30 km/h).
Adjusting the set speedAfter a speed has been set, it can be increased
or decreased by using the
or buttons.
1.
Press and hold down
or until the
vehicle reaches the desired speed.
> This will become the set speed when the
button is released.
2.
Press
or for approximately a half
second and release the button to increase
or decrease vehicle speed by approxi-
mately 1 mph (1.6 km/h).
NOTE
•A temporary increase in speed by
pressing the accelerator pedal, for less
than 1 minute (e.g. when passing
another car), does not affect the current
cruise control setting. The vehicle will
automatically return to the previously
set speed when the accelerator pedal is
released.
•If one of the cruise control buttons is
kept depressed for more than approx.
1 minute cruise control is disengaged.
The engine must then be switched off in
order to reset cruise control.
Automatic deactivationCruise control is automatically deactivated
temporarily if one of the following occurs:
•If the speed drops below approximately
20 mph (30 km/h).
•When the brake pedal is depressed.
•If the gear selector is moved to position N.
•During wheel spin or wheel lock-up.
•If the vehicle's speed is increased by using
the accelerator pedal for more than
1 minute.
The currently set speed will be saved in the
system's memory.

04 Comfort and driving pleasure
Adaptive Cruise Control (ACC)*
04
162* Option/accessory, for more information, see Introduction.
Introduction
Adaptive Cruise Control (ACC) is an optional
system designed to assist the driver by main-
taining a set speed or a set time interval to the
vehicle ahead. It is primarily intended for use
on long straight roads in steady traffic, such as
on highways and other main roads.
When the driver has set the desired speed and
the time interval to the vehicle ahead, ACC
functions as follows:
•If there are no other vehicles in the lane
ahead of you, your vehicle will travel at the
set speed.
•If ACC's radar sensor detects a slower
moving vehicle in the lane ahead, the sys-
tem will adapt your vehicle's speed to help
maintain the set time interval to the vehicle
ahead. When there are no longer slower
moving vehicles ahead, your vehicle will
accelerate to resume the set speed.
If ACC is switched off completely or in standby
mode and your vehicle comes too close to
another vehicle ahead, the driver will be
warned by the Distance Alert system (see
page 171).
WARNING
•Adaptive Cruise Control cannot cover
all driving situations and traffic, weather
and road conditions. The "Function"
section provides information about lim-
itations that the driver must be aware of
before using this feature.
•This system is designed to be a supple-
mentary driving aid. It is not, however,
intended to replace the driver's atten-
tion and judgement. The driver is
responsible for maintaining a safe dis-
tance and speed and must intervene if
Adaptive Cruise Control does not main-
tain a suitable speed or suitable dis-
tance to the vehicle ahead.
•Maintenance of ACC components may
only be performed by a trained and
qualified Volvo technician.
Function
G021412
Function overview
Warning light, braking by driver required
Controls in steering wheel
Radar sensor in front grille
Adaptive Cruise Control consists of:
•A cruise control system to maintain a set
speed
•A system to maintain a set distance to the
vehicle ahead, which is expressed as a
time interval. For example, you can choose
to remain approximately 2 seconds behind
the vehicle ahead. The actual distance
required to maintain a 2-second interval
will vary according the speed of the vehi-
cles.

04 Comfort and driving pleasure
Adaptive Cruise Control (ACC)*
04
166* Option/accessory, for more information, see Introduction.
Standby mode due to action by the driverACC is temporarily deactivated and put in
standby mode:
•when the brakes are applied
•if the gear selector is moved to N
•if the accelerator pedal is depressed for
more than 1 minute.
NOTE
If the accelerator pedal is only depressed for
a short time, such as when passing another
vehicle, ACC is deactivated temporarily and
is reactivated when the pedal is released.
Automatic standby modeAdaptive cruise control is linked to other sys-
tems such as the stability and traction control
system (DSTC). If this system is not functioning
properly, adaptive cruise control is automati-
cally deactivated and will go into standby
mode.
In the event of automatic deactivation, an audi-
ble signal will sound and the message
Cruise
control Cancelled is shown in the display.
The driver must then intervene and adapt the
vehicle's speed to the surrounding traffic and
regulate the distance to the vehicle ahead.
An automatic switch to standby mode may be
caused if:
•the vehicle's speed falls below 20 mph
(30 km/h)
•the wheels lose traction
•brake temperature is high
•engine speed (rpm) is too low or too high
•the radar sensor is obstructed by, for
example, wet snow or rain.
Turning ACC off completely
A short press on in standby mode or a long
press in active mode turns ACC off completely.
The set speed and time interval are then
cleared from the system's memory and cannot
be resumed by pressing
.
The radar sensor and its limitations
In addition to being used by ACC, the radar
sensor is also used by Distance Alert (see
page 171) and Collision Warning with Auto-
brake (see page 174). This sensor is designed
to detect cars or larger vehicles driving in the
same direction as your vehicle, in the same
lane.
WARNING
Accessories or other objects, such as extra
headlights, must not be installed in front of
the grille.
Modification of the radar sensor could make
its use illegal.
The radar sensor's capacity to detect vehicles
ahead is impeded:
•if the radar sensor is obstructed and can-
not detect other vehicles, for example in
heavy rain, or if snow or other objects are
obscuring the radar sensor.
NOTE
Keep the area in front of the radar sensor
clean.
•if the speed of vehicles ahead is signifi-
cantly different from your own speed.

04 Comfort and driving pleasure
Collision warning with Auto-brake*
04
176* Option/accessory, for more information, see Introduction.
NOTE
•When Adaptive Cruise Control is used,
the warning light and signal will be used
by that function, even if the warnings
provided by Collision Warning have
been deactivated by the driver.
•In situations where traffic is moving at
considerably different speeds, or if the
vehicle ahead brakes suddenly, warn-
ings may be considered to be late, even
if the setting
Long has been selected.
Checking settingsThe current Collision Warning settings can be
checked by going into the menu system at Car
settings
Collision warning settings.
See page 124 for more information on the
menu system.
Limitations
Strong sunlight, reflections, extreme light con-
trasts, the use of sunglasses, or if the driver is
not looking straight ahead may make the visual
warning signal in the windshield difficult to see.
For this reason, always activate the audible
warning signal.
Slippery driving conditions increase braking
distance, which can reduce the system's
capacity to avoid a collision. In these condi-tions, the ABS and DSTC systems provide the
best possible braking effect while helping to
maintain stability.
NOTE
The visual warning signal may be temporar-
ily disengaged in the event of high passen-
ger compartment temperature due to strong
sunlight, etc. If this occurs, the audible
warning signal will be used, even if it has
been deactivated in the menu system.
WARNING
•In certain situations, the system cannot
provide warnings or warnings may be
delayed if traffic conditions or other
external factors make it impossible for
the radar sensor or camera to detect a
vehicle ahead.
•Warnings may not be provided if the
distance to the vehicle ahead is short,
or if movements of the steering wheel/
brake pedal are great, such as during
active driving.
•The sensor system has a limited range
for stationary or slow-moving vehicles
and may therefore give delayed or no
warnings if your vehicle’s speed is
above approximately 45 mph
(70 km/h).
•Warnings for stationary or slow-moving
vehicles may not be provided in dark
conditions.
The Collision Warning system uses the same
radar sensors as Adaptive Cruise Control. For
more information on the radar sensor and its
limitations, see page 166.
If no warning is given, or if a warning is delayed,
Auto-brake will also not be provided or will be
delayed.

04 Comfort and driving pleasure
Driver Alert System*
04
180* Option/accessory, for more information, see Introduction.
Introduction
The Driver Alert System is designed to help a
driver who may be becoming fatigued or who
is inadvertently leaving the lane.
The Driver Alert System consists of two differ-
ent functions that can be switched on together
or separately.
•Driver Alert Control (DAC)
•Lane Departure Warning (LDW), see
page 183
When one or both of the functions has been
switched on, it is in standby mode and is acti-
vated when the vehicle exceeds a speed of
40 mph (65 km/h).
The function deactivates if speed goes under
37 mph (60 km/h).
Both functions use a camera that is dependent
on the road/lane being clearly marked by pain-
ted lines on each side.
WARNING
The Driver Alert system does not function in
all situations and is designed to be a sup-
plementary aid. It is not, however, intended
to replace the driver’s attention and judge-
ment.
Driver Alert Control (DAC)–
introduction
This function is intended to alert the driver if
his/her driving becomes erratic, such as if the
driver is distracted or fatigued.
NOTE
The camera has certain limitations, see
page 166.
A camera monitors the painted lines marking
the lane in which the vehicle is traveling and
compares the direction of the road with the
driver’s movements of the steering wheel. The
driver is alerted if the vehicle does not follow
the lane smoothly.DAC is designed to help detect a slowly chang-
ing driving pattern. It is primarily intended to be
used on main roads and is not meant for use in
city traffic.
WARNING
•DAC is not intended to extend the dura-
tion of driving. Always plan breaks at
regular intervals to help remain alert.
•In certain cases, fatigue may not affect
the driver’s behavior. In situations of
this type, no warning will be provided.
Therefore, it is important to take breaks
at regular intervals, regardless of
whether or not DAC has given a warn-
ing.
LimitationsIn certain situations, DAC may provide warn-
ings even if the driver’s driving pattern has not
become erratic.
•if the driver is testing the LDW function
•in strong crosswinds
•on grooved road surfaces.

04 Comfort and driving pleasure
Driver Alert System*
04

* Option/accessory, for more information, see Introduction.181 Operating DAC
Certain settings can be made from the menu
system controlled from the center instrument
panel.
The current system status can be checked on
the trip computer’s display by using the but-
tons on the left steering wheel lever.
Thumb wheel. Turn this wheel until Driver
Alert is displayed. The second line shows
the alternatives Off, Unavailable, or [-----
], i.e., the number of bars.
READ button. Confirms and erases a mes-
sage in the display.
Activating DACIn the center instrument panel, go to Car
settings and select Driver Alert on.
The function is activated when the
vehicle exceeds a speed of 40 mph
(65 km/h). The display will show level
markings of 1–5 bars, where a low
number of bars indicates erratic driving. A high
number of bars indicates stable driving.
If the vehicle is being driven erratically, the
driver will be alerted by an audible signal and
the message Driver Alert, Time for a break is
displayed. The warning will be repeated after a
short time if the driving pattern remains the
same.
WARNING
•An alert should be taken seriously since
it is sometimes difficult for a driver to
realize that he/she is fatigued.
•In the event of a warning or if the driver
feels fatigued, stop as soon as possible
in a safe place and rest.
Symbols and messages in the display
SymbolMessageDescription
-Driver alert offThe function is not switched on.
-Driver alert
UnavailableThe vehicle’s speed is below 37 mph (60 km/h) or the road lacks clear marking lines.