2015 VOLVO XC70 engine

03 Your driving environment
Hill Descent Control (HDC)*
03
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* Option/accessory, for more information, see Introduction.147
Introduction
Normally, when the accelerator pedal is released while driving down hills, the vehicle'sspeed slows as the engine runs at lower rpm(the normal engine braking effect). However, ifthe downhill gradient becomes steeper and ifthe vehicle is carrying a load, speed increasesdespite the engine braking effect. In this sit-uation, the brakes must be applied to reducethe vehicle's speed. HDC is a type of automatic engine brake and makes it possible to increase or decrease thevehicle's speed on downhill gradients usingonly the accelerator pedal, without applyingthe brakes. The brake system functions auto-matically to maintain a low and steady speed. HDC is particularly useful when driving down steep hills with rough surfaces, and where theroad may have slippery patches.
WARNING
HDC does not function in all situations, and is a supplementary braking aid. Thedriver has full responsibility for driving in asafe manner.
Function
• HDC can be switched on and off with the button in the center console. An indicatorlight in the button illuminates when HDCis activated.
• The indicator light
in the instru-
ment panel illuminates and a message is displayed when the system is controllingthe vehicle's speed.
• HDC only functions when
first or reverse
gears are selected (
1 will be shown in the
instrument panel display when first gear is selected).
NOTE
HDC cannot be activated if the gear selec- tor is the D position.
Using HDC
HDC allows the car to roll forward at a maxi- mum speed of 6 mph (10 km/h), and 4 mph(7 km/h) in reverse. However, the acceleratorpedal can be used to select any speed that ispossible in first or reverse gears. When theaccelerator pedal is released, speed isquickly reduced again to 6 mph (10 km/h) or4 mph (7 km/h), depending on the gearselected, regardless of the hill's gradient. It isnot necessary to apply the brakes.
• The brake lights illuminate automatically when HDC is controlling the vehicle'sspeed.
• The driver can slow or stop the vehicle atany time by applying the brakes.
HDC is deactivated when:
• The button on the center console ispressed
• A gear higher than first gear is selected
• D
is selected on vehicles with an auto-
matic transmission
HDC can be deactivated at any time. If this is done while driving down a steep hill, the sys-tem's braking effect will decrease gradually.

03 Your driving environment
Hill Descent Control (HDC)*
03
148* Option/accessory, for more information, see Introduction.
NOTE
Engine response to pressure on the accel- erator pedal may be slightly slower thannormal when HDC is activated.

04 Driver support
Stability system
04
152
Introduction
The Dynamic Stability and Traction Control system (DSTC) consists of a number of func-tions designed to help reduce wheel spin,counteract skidding, and to generally helpimprove 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 drivewheel that begins to lose traction to thewheel on the opposite side of the vehicle (onthe 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 brakingone or more of the wheels if the vehicleshows a tendency to skid or slide laterally.This is one of DSTC's permanent functionsand cannot be switched off.
Spin control (SC)The spin control function is designed to helpprevent the drive wheels from spinning whilethe vehicle is accelerating.
Trailer Stability Assist – TSA
1Trailer Stability Assist helps stabilize a vehiclethat is towing a trailer when the vehicle andtrailer have begun to sway. See page 304 formore information. This system is automatically deactivated if the driver selects
Sport mode.
Operation
Sport modeThe stability system is always activated and cannot be switched off. However, the driver can select Sport mode,
which offers more active driving characteris- tics. In this mode, the engine managementsystem monitors movement of the acceleratorpedal and steering wheel for sportier driving by allowing more lateral movement of the rearwheels before DSTC is activated. Under certain circumstances, such as when driving with snow chains, or driving in deepsnow or loose sand, it may be advisable totemporarily use
Sport mode for maximum
tractive force. If the driver releases pressure on the acceler- ator pedal, DSTC will also activate to helpstabilize the vehicle. To switch to Sport mode:
1. Press the My Car button in the center
console control panel and select
My
XC70
DSTC in the menu.
2. Unselect the symbol and leave the menu by pressing EXIT.
> This puts DSTC in Sport mode.
Sport mode remains active until the driver
switches it off in the menu or until the engine is switched off. DSTC will return to normalmode when the engine is restarted.
1 Included when a Volvo trailer hitch is installed

04 Driver support
Stability system
04
153
Symbols and messages in the main instrument panel
SymbolMessageDescription
DSTC Temporarily OFFThe DSTC system function has been temporarily reduced due to high brake disc temperature. DSTC reactivates automatically when the brakes have cooled.
DSTC Service requiredThe DSTC system is not functioning properly.
• Stop the vehicle in a safe place, turn off the engine and restart it.
• If the message is still displayed when the engine has restarted, drive to an authorized Volvo work- shop to have the system inspected.
and
"Message"Read the message in the instrument panel
Steady glow for 2 secs.The system is performing a self-diagnostic test.
Flashing symbolDSTC is actively functioning to help counteract wheel spin and/or a skid.
-Sport
mode has been activated.
WARNING
The stability system is intended to help improve driving safety. It supplements, butcan never replace, the driver's judgmentand responsibility when operating the vehi-cle. Speed and driving style should alwaysbe adapted to traffic and road conditions.

04 Driver support
Cruise control
04
156
Operation
Steering wheel-mounted controls and display
Standby mode
Resume set speed
Deactivating
Activate/set speed
Selected speed (gray symbol indicates
standby mode)
Cruise control active: white symbol ( gray
symbol indicates standby mode)
Engaging the cruise control functionBefore a speed can be set, the cruise control system must be engaged (put in standbymode).
–Press the CRUISE button (1).
> The symbol
illuminates and the text
(---) mph (5) indicates that cruise con-
trol is in standby mode.
NOTE
Putting cruise control in standby mode does not set a cruising speed.
Setting a speed
Use the or buttons set the vehicle's
current speed. The set speed is shown in the display.
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
or briefly and release the
button to increase or decrease vehicle speed by approximately 5 mph (8 km/h).
> This will become the set speed when the button is released.
2. To adjust the speed in increments of 1 mph (approx. 2 km/h), press and hold down
or until the vehicle reaches
the desired speed.
NOTE
• A temporary increase in speed by pressing the accelerator pedal, for lessthan 1 minute (e.g. when passinganother car), does not affect the cur-rent cruise control setting. The vehiclewill automatically return to the previ-ously set speed when the acceleratorpedal is released.
• If one of the cruise control buttons iskept depressed for more than approx.1 minute cruise control is disengaged.The engine must then be switched offin order to reset cruise control.

04 Driver support
Cruise control
04
157
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 positionN.
• During wheel spin or wheel lock-up.
• If the vehicle's speed is increased byusing the accelerator pedal for more than1 minute.
The currently set speed will be saved in the system's memory.
Temporary deactivationThe driver can temporarily deactivate cruisecontrol by pressing 0. The saved speed is
shown in brackets in the information display.
Resume set speedIf cruise control has been deactivated tempo- rarily, it can be reactivated by pressing
.
The vehicle's speed returns to the most recently set speed.
WARNING
There may be a significant increase in speed after the
button has been
pressed.
Deactivation
Cruise control is disengaged by pressing or by switching off the engine. The set speed is cleared.
WARNING
Cruise control should not be used in heavy traffic or when driving on wet or slipperyroads. Cruise control may not maintain setspeed on steep downgrades.

04 Driver support
Adaptive Cruise Control (ACC)*
04
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* Option/accessory, for more information, see Introduction.159
2-second interval will vary according the speed of the vehicles.
WARNING
•
Adaptive Cruise Control is not a colli- sion avoidance system. The driver isalways responsible for applying thebrakes if the system does not detectanother vehicle.
• Adaptive Cruise Control does not reactto people or animals, or small vehiclessuch as bicycles and motorcycles. Italso does not react to slow moving,parked or approaching vehicles, orstationary objects.
• Do not use Adaptive Cruise Control indemanding driving conditions such ascity driving or other heavy traffic situa-tions, in slippery conditions, whenthere is a great deal of water or slushon the road, during heavy rain orsnow, in poor visibility, on windingroads or on highway on- or off-ramps.
The distance to the vehicle ahead (in the same lane) is monitored by a radar sensor.Your vehicle's speed is regulated by acceler-ating and braking. The brakes may emit asound when they are being modulated by the adaptive cruise control system. This is nor-mal.
WARNING
The brake pedal moves when the adaptive cruise control system modulates thebrakes. Do not rest your foot under thebrake pedal.
The ACC system is designed to smoothly regulate speed. However, the driver mustapply the brakes in situations that requireimmediate braking. This applies when thereare great differences in speed between vehi-cles, or if the vehicle ahead brakes suddenly.
WARNING
Due to limitations in the radar sensor, braking may occur unexpectedly or not atall, see page 165.
Adaptive Cruise Control can be put in active mode at any permitted speed. However, if thevehicle's speed falls below 18 mph (30 km/h)or if engine speed (rpm) becomes too low,ACC disengages (goes into standby mode)and will no longer modulate the brakes. Thedriver will then have to maintain a safe dis-tance to the vehicle ahead.
WARNING
When Adaptive Cruise Control is in standby mode or is switched off com-pletely, the brakes will not be modulatedautomatically. The driver must assume fullcontrol over the vehicle.
Warning light—driver braking requiredAdaptive Cruise Control can exert brake force that is equivalent to approximately 40% ofthe vehicle's total braking capacity. In situa-tions requiring more brake force than ACCcan provide and if the driver does not applythe brakes, an audible signal from the Colli-sion Warning system will sound and warninglight will illuminate (see page 179) in thewindshield to alert the driver to react.
NOTE
Strong sunlight, reflections, extreme light contrasts, the use of sunglasses, or if thedriver is not looking straight ahead maymake the visual warning signal in the wind-shield difficult to see.

04 Driver support
Adaptive Cruise Control (ACC)*
04
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* Option/accessory, for more information, see Introduction.161
When this symbol has changed col- ors from
white to green , ACC is in
active mode and the vehicle will
maintain the set speed.
This symbol indicates that you are approaching a vehi-cle ahead. ACC will switch from main- taining a set speed to main-
taining a set distance from
that vehicle.
When this happens, a speed range will be indicated on
the speedometer: The higher speed (the cur-
rently set speed (5)) will be marked in green.
The lower speed in the range is the speed of
the vehicle ahead.
Changing the set speed
• After a speed has been set, it can be increased or decreased by briefly press- ing the
or buttons. Each time one
of these buttons is pressed, the vehicle's speed changes by 3 mph(approximately 5 km/h). If the speed isincreased by pressing the accelerator pedal, the vehicle's speed when the but-ton is pressed will be set.
• Press and hold one of the buttons toincrease/decrease the speed by 1 mph(approximately 1 km/h) at a time. Releasethe button when you have reached thedesired speed.
NOTE
•If one of the Adaptive Cruise Control buttons is pressed for more thanapproximately one minute, ACC will bedeactivated. The engine must then beswitched off and restarted to resetACC.
• In some situations Adaptive CruiseControl cannot be put in active mode.
Cruise control Unavailable is shown
in the display, see page 167.
Setting a time intervalThe set time interval to vehicles ahead can be increased by pressing
and decreased by
pressing
. The current time interval is
shown briefly in the display following adjust- ment. Different time intervals canbe selected and are shown in the instrument panel
2
as 1–5
horizontal bars. The greater the number of bars, thelonger the time interval. Onebar represents a time interval
of approximately 1 second; 5 bars is approxi-mately 3 seconds.
To set/change a time interval:
• Press the
/ buttons (3).
At low speeds, when the distance to the vehi- cle ahead is short, ACC increases the timeinterval slightly. In order to follow the vehicleahead as smoothly as possible, ACC allowsthe time interval to vary considerably in cer-tain situations.
WARNING
• Only use a time interval that is suitable in current traffic conditions.
• A short time interval gives the driverlimited reaction time if an unexpectedsituation occurs in traffic.
2
The same symbol appears if Distance Alert (see page 169) is activated