2020 VOLVO S90 brakes

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390
Activating and deactivating Auto- hold at a standstill
The Auto-hold brake function at a standstill is activated with the button in the tunnel con-sole.
–Press the button in the tunnel console to activate or deactivate the function.
> The indicator light in the button will illu- minate when the function is activated. The function will remain active the nexttime the vehicle is started.
When shutting offIf the function is active and holdingthe vehicle stationary using the nor-mal brakes (A symbol lit in theinstrument panel), the brake pedal
must be depressed while pressing the buttonin order to deactivate Auto-hold.
The function will remain off until it is reac- tivated.
When Auto-hold is switched off, Hill StartAssist (HSA) will remain active to helpprevent the vehicle from rolling backwardwhen starting up a hill.
Related information
Auto-hold brakes (p. 389)
Hill Start Assist
The function for assisting when starting the vehicle on inclines (HSA 4
) helps prevent the
vehicle from rolling backward when starting on an uphill gradient. When backing up a hill,HSA helps prevent the vehicle from rollingforward.
The function retains pressure from the brake pedal in the brake system for several secondsafter the brake pedal has been released. This temporary braking effect is released after a few seconds or when the driver begins driv-ing. Hill Start Assist is available even when the Auto-hold brake function is switched off.
Related information
Auto-hold brakes (p. 389)
Brakes (p. 383)

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* Option/accessory.391
Braking assist after a collision
In a collision in which the activation level is reached for the pyrotechnic seat belt tension-ers or airbags, or if a collision with a large ani-mal is detected, the vehicle's brakes will beautomatically activated. This function isintended to help prevent or reduce the effectsof any subsequent collision.
After a serious collision, it may no longer be possible to control and steer the vehicle. Inorder to avoid or mitigate a possible furthercollision with a vehicle or an object in the vehi-cle's path, the brake assist system is activatedautomatically to help stop the vehicle safely. If braking is not appropriate, e.g. if there is a risk of being hit by passing traffic, the drivercan override the system by depressing theaccelerator pedal. This function assumes that the brake system is intact after a collision.
Related information
Rear Collision Warning
* (p. 326)
BLIS
* (p. 327)
Brake functions (p. 382)
Transmission
The transmission is part of the vehicle's drive- line (power transmission) between the engineand the drive wheels. The function of thetransmission is to change gears dependingon speed and power needs.
The vehicle has an 8-speed automatic trans- mission. The number of gears allows theengine's torque and power band to be effec-tively utilized. Two of the gears are overdrivegears that save fuel when driving at a constantengine speed. Manual shifting is also possible.The instrument panel shows the gear currentlyin use.
Related information
Automatic transmission (p. 391)
Automatic transmission
In vehicles with an automatic transmission, the system selects the gear so that drivingwill be as energy-efficient as possible. Thetransmission also has a manual mode.
The transmission is available in different ver- sions. The gear selector indicates which trans-mission the vehicle has. The various gearselectors have different functions.
Overview of large gear selector and gear shift pattern in the instrument panel
4 Hill Start Assist

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* Option/accessory.399
All Wheel Drive (AWD) *
All-wheel drive (AWD 8
), also called four-
wheel drive, means that power is distributed to all four wheels, which improves traction.
To achieve the best traction, power is auto- matically directed to the wheels that have thebest grip. The system continuously calculatesthe need for torque to the rear wheels, andcan immediately redistribute up to half of theengine's torque to the rear wheels. All-wheel drive also has a stabilizing effect at higher speeds. In normal driving conditions,most of the engine's power is directed to thefront wheels. When the vehicle is stationary,all-wheel drive is always activated in prepara-tion for maximum traction during acceleration. All-wheel drive reacts differently depending on which drive mode is selected.
Related information
Drive modes
* (p. 399)
Transmission (p. 391)
Drive modes
*
Drive modes affect the vehicle's driving cha- racteristics in different ways to enhance andsimplify the driving experience in certaintypes of situations.
Drive modes enable easy access to the vehi- cle's many functions and settings in differentdriving situations. The following systems areadapted to help optimize driving characteris-tics in each drive mode: Steering
Engine/transmission/all-wheel drive
*
Brakes
Shock absorbers
Instrument panel
Start/Stop function
Climate control settings
Select the drive mode that is adapted to the current driving conditions. Keep in mind thatnot all drive modes are available in all situa-tions.
Available drive modesWhen the engine is started, the vehicle will be in Comfort mode and the start/stop function
will be activated. Drive mode can be changed once the vehicle is started, e.g. to
Individual
mode. Once Individual mode is selected, you
can adjust settings to personal preferences, e.g. to show the tachometer.
Comfort
Comfort is the vehicle's default mode. This
setting offers driving comfort, light steering and soft suspension. In
Comfort mode, no tachometer will be dis-
played in the instrument panel 9
.
Eco
Adapt the vehicle for more fuel-efficient and eco-friendly driving with Eco mode.
In this mode, the Start/Stop function is acti- vated and certain climate settings arereduced. When driving in
Eco mode, an ECO gauge
indicating how economical the driving is will be displayed in the instrument panel.
8 All Wheel Drive
9 Only applies to vehicles with 8-inch instrument panels.

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* Option/accessory.
402 This function is most effective in driving situa- tions where the vehicle can roll freely for along distance, e.g. on roads with slight down-grades or when a decrease in speed is antici-pated, such as when approaching an area witha lower speed limit.
Activating Eco Coast
The function is activated when the accelerator pedal is fully released and the following condi-tions are met:
Eco drive mode is activated.
The gear selector is in
D.
The vehicle's speed is approximately 65-140 km/h (40-87 mph).
The gradient of the downgrade is less thanapproximately 6%.
COASTING will be displayed in the instrument
panel when Eco Coast is being used.
Limitations
Eco Coast is not available if
the engine and/or transmission are not at normal working temperatures
the gear selector is moved from
D to man-
ual shifting mode
the vehicle's speed is not within the65-140 km/h (40-87 mph) range
the gradient of the downgrade is morethan approximately 6%
The steering wheel paddles
* are being
used for manual shifting.
Deactivating and turning off Eco Coast
In certain situations, it may be advisable to deactivate or turn off Eco Coast so that enginebraking can be used. These situations mightinclude driving down steep hills or beforepassing another vehicle to help ensure thiscan be done as safely as possible. Deactivate Eco Coast by
pressing the accelerator or brake pedal
moving the gear selector to manual mode
Using the steering wheel paddles
* to shift.
Turn off Eco Coast by
switching to another drive mode
*
deactivating
Eco drive mode in Function
view.
It is possible to roll short distances even with- out Eco Coast in order to help conserve fuel.However, for the best fuel economy, EcoCoast should be activated and used to rolllonger distances.
Cruise control Eco CruiseWhen cruise control is activated in the Ecodrive mode, the vehicle's acceleration and deceleration will be slower than in other drivemodes to help further conserve fuel. Becauseof this, the vehicle's actual speed may beslightly above or below the set speed.
On a level road, the vehicle's actual speedmay differ from the set speed when cruisecontrol is active and the vehicle is coast-ing.
On a steep uphill gradient, the vehicle'sspeed is reduced until the transmissiondownshifts. Reduced acceleration is theninitiated in order to reach the set speed.
On a downhill gradient in which the vehi-cle is coasting, the vehicle's actual speedmay be slightly above or below the setspeed. The function uses engine brakingto keep the set speed. If necessary, thenormal brakes are also applied.

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Stop the vehicle by applying the brakes and keep the brake pedal depressed. Theengine will auto-stop.
In
Comfort or Eco drive mode, the engine
may auto-stop before the vehicle has com- pletely stopped. With Adaptive Cruise Control or Pilot Assist activated, the engine will auto-stop aboutthree seconds after the vehicle has stopped.
Auto-startThe following conditions must be met for theengine to auto-start.
Release the brake pedal. The engine willauto-start and the vehicle can be driven.On an uphill gradient, Hill Start Assist (HSA 12
) will activate to help prevent the
vehicle from rolling backward.
When the Auto-hold function is activated, auto-start will be delayed until the acceler-ator is pressed.
When Adaptive Cruise Control or PilotAssist are activated, the engine will auto- start when the accelerator pedal is depressed or the
button on the left-
side steering wheel keypad is pressed.
Maintain pressure on the brake pedal and press the accelerator pedal. The enginewill auto-start.
On a downhill gradient: Release the brakepedal slightly so that the vehicle begins toroll. The engine will auto-start after a slightincrease in speed.
Symbols in the instrument panel
The symbol will be displayed in
the tachometer when the function is avail- able.
An indicator in the tachometer will point toward
when Start/Stop is active
and the engine has auto-stopped.
The
symbol will be grayed-out
when the function is not available.
No symbol will be shown when the func- tion is turned off.
The function is active and the engine has auto-stop- ped.
On vehicles with the 8-inch instrument panel, the symbol will be shown at the bottom of thespeedometer.
Related information
Deactivating the Start/Stop function(p. 406)
Conditions for the Start/Stop function(p. 406)
Start/Stop function (p. 404)
Hill Start Assist (p. 390)
Auto-hold brakes (p. 389)
12
Hill Start Assist

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412
WARNING
Never turn off the engine while the vehicle is moving, e.g. when driving downhill. Thisdeactivates certain important systemssuch as power steering and brakes.
Other factors that decrease fuel consumption
Dirty air cleaner.
Dirty engine oil and clogged oil filter.
Incorrect front-end alignment.
Incorrect wheel alignment.
Some of the above items and others are checked as part of Volvo's standard mainte-nance schedule.
Related information
Drive-E
‒ purer driving pleasure (p. 28)
Eco drive mode (p. 401)
Checking tire pressure (p. 507)
Preparing for a long trip
It is important to have the vehicle's systems and equipment checked carefully before driv-ing long distances.
Check that
the engine is running properly and that fuel consumption is normal
there are no leaks (fuel, oil or other fluid)
the brake pedal is functioning properly
all lights are working
‒ adjust the head-
light height if the vehicle is carrying aheavy load
tire tread depth and air pressure are atcorrect levels. Change to snow tires whendriving in areas where there is a risk ofsnowy or icy roads
the start battery is sufficiently charged
the wiper blades are in good condition
Related information
Checking tire pressure (p. 507)
Filling washer fluid (p. 607)
Winter driving (p. 412)
Economical driving (p. 411)
Vehicle modem settings (p. 483)
Loading recommendations (p. 538)
Pilot Assist
* (p. 285)
Tire sealing system (p. 523)
Winter driving
It is important to check the vehicle before driving in cold/snowy conditions to makesure it can be driven safely.
Before the cold season arrives: Make sure the engine coolant contains 50% antifreeze. This mixture helps pro-tect the engine from frost erosion down toapprox. –35 °C (–31 °F). Do not mix dif-ferent types of antifreeze as this couldpose a health risk.
Keep the fuel tank well filled to preventcondensation from forming.
Check the viscosity of the engine oil. Oilwith low viscosity (thinner oil) improvescold-weather starting and reduces fuelconsumption when driving with a coldengine.
CAUTION
Low-viscosity oil should not be used with hard driving or in hot weather.
Check the condition and charge level of the start battery. Cold weather placesgreater demands on the start battery andreduces its capacity.
Use washer fluid containing antifreeze tohelp prevent ice from forming in thewasher fluid reservoir.

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Slippery driving conditionsTo help optimize traction and roadholding, Volvo recommends using snow tires on allwheels whenever there is a risk of snow or iceon the road.
NOTE
Certain countries require use of winter tires by law. Not all countries permit the use ofstudded tires.
Practice driving on slippery surfaces under controlled conditions to learn how the vehiclereacts.
Related information
Snow tires (p. 521)
Snow chains (p. 522)
Braking on salted roads (p. 385)
Braking on wet roads (p. 384)
Filling washer fluid (p. 607)
Start battery (p. 567)
Replacing windshield wiper blades(p. 605)
Refilling coolant (p. 556)
Driving through standing water
It may be necessary to drive the vehicle through standing water, e.g. deep puddles orflooding on the road. This must be done withgreat caution.
The vehicle can be driven through water up to a depth of 25 cm (9 in) at no more than walk-ing speed. Be particularly careful when drivingthrough flowing water. When driving through standing water, drive slowly and do not stop the vehicle. When youhave passed the water, press lightly on thebrake pedal and check that the brakes arefunctioning properly. Water, mud, slush, etc.can make the brake linings slippery, resultingin delayed braking effect. If the vehicle is equipped with contacts for an electric heater or trailer coupling, cleanthese after driving in water or mud.
Do not allow the vehicle to stand in waterup to the sills any longer than absolutelynecessary. This could result in electricalmalfunctions.
CAUTION
Engine damage could occur if water enters the air cleaner.
If water enters the transmission, thelubricating ability of the oils is reducedand the service life of these systems isshortened.
Damage to any component, engine,transmission, turbocharger, differentialor its internal components caused byflooding, vapor lock or insufficient oil isnot covered under warranty.
If the engine stalls while the vehicle isin water, do not attempt to restart it.Have the vehicle towed out of thewater to a workshop. An authorizedVolvo workshop is recommended. Riskof engine failure.
CAUTION
Because it can be difficult to determine the water depth, Volvo recommends not driv-ing through standing or running water. Thedriver is always responsible for operatingthe vehicle in a safe manner and adheringto all applicable laws and regulations.
Related information
Recovery (p. 425)

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423
5. Keep the towline taut when the towing
vehicle slows down by applying light pres- sure to the brake pedal. This will helpavoid jarring movements.
6. Be prepared to apply the brakes to stop the vehicle.
Jump startingDo not tow the vehicle to start the engine. Usean auxiliary battery if the start battery's chargelevel is so low that the engine cannot bestarted.
CAUTION
Attempting to tow with the engine running could result in damage to the three-waycatalytic converter.
Related information
Attaching and removing the towing eyelet (p. 423)
Hazard warning flashers (p. 157)
Recovery (p. 425)
Jump starting using another battery(p. 420)
Selecting ignition mode (p. 382)
Transmission (p. 391)
Attaching and removing the towing eyelet
Use the towing eyelet when towing. Screw the towing eyelet securely into place in thethreaded outlet behind the cover on the right-hand side of the front and rear bumpers.
NOTE
If the vehicle is equipped with a towbar, there is no rear attachment for the towingeye.
Attaching the towing eyelet
Take out the towing eyelet, which is stored in a foam block under the floor inthe cargo compartment.
Front: Remove the cover by pressing on the mark with a finger.
> The cover turns along its center line and can then be removed.