brakes VOLVO S90 TWIN ENGINE 2020 Service Manual

STARTING AND DRIVING
406
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. Main- tain an extra large safety distance to the vehi-cle ahead. Make sure to also:
Apply the brakes from time to time to helpremove salt. Make sure braking does notpose a risk to any other road users.
Gently apply the brakes when you havefinished driving and before driving again.
Related information
Brakes (p. 403)
Braking on wet roads (p. 405)
Maintenance of the brake system
Regularly check the brake system compo- nents for wear.
To keep the vehicle as safe and reliable as possible, follow the Volvo service schedulespecified in the Warranty and MaintenanceRecords Information booklet. After replacingbrake pads and brake discs, braking effect isnot adapted until they are "broken in" by driv-ing a few hundred kilometers (miles). Com-pensate for the reduced braking effect byapplying greater pressure to the brake pedal.Volvo recommends only using brake padsapproved 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 theinspection - an authorized Volvo workshopis recommended.
Related information
Brakes (p. 403)
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 thebrake's electric motor. This sound can also beheard during the automatic function check ofthe parking brake. If the vehicle is stationary when the parking brake is activated, it will only be applied to therear wheels. If it is activated while the vehicleis moving, the normal brakes will be used onall four wheels. Braking will be transferred toonly the rear wheels when the vehicle isalmost stopped.

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407
Related information
Activating and deactivating the parking brake (p. 407)
Parking on a hill (p. 409)
Parking brake malfunction (p. 409)
Auto-hold brakes (p. 410)
Activating and deactivating the parking brake
Use the parking brake to help keep the vehi- cle stationary when it is parked.
Activating the parking brake
1. Pull up the control.
> The symbol in the instrument panel willilluminate when the parking brake is activated.
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. Readthe message in the instrumentpanel.
A
Canadian models.
B US models.
Automatic activation
The parking brake is applied automatically when the ignition is switched off and the setting for automatically activating theparking brake is activated in the centerdisplay.
when the gear selector is moved to
P on a
steep hill.
if the auto-hold brake (automatic brake atstandstill) function is activated and
the vehicle has been stationary for aprolonged period of time (5-10minutes).
the vehicle is switched off.
the driver has left the vehicle.

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STARTING AND DRIVING
410
Related information
Activating and deactivating the parking brake (p. 407)
Parking on a hill (p. 409)
Start battery (p. 579)
Volvo's service program (p. 562)
Auto-hold brakes
With the Auto-hold brake function, the driver can release the brake pedal and the brakeswill remain applied, for example, when thevehicle has stopped at a traffic light or inter-section.
When the vehicle stops, the brakes are acti- vated automatically. The function can useeither the normal brakes or the parking brakesto keep the vehicle stationary and works onflat surfaces or hills. If the driver has their seatbelt fastened or if the driver's door is closed,the brakes will disengage automatically whenthe vehicle starts driving.
NOTE
When braking to a stop on an uphill or downhill gradient, depress the brake pedalwith slightly more force than usual beforereleasing to ensure that the vehicle cannotmove 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 normalbrakes to keep the vehicle sta-tionary.
A
B This symbol illuminates when the function is using the parkingbrake to keep the vehicle station-ary.
A
Canadian models.
B US models.
Related information
Activating and deactivating Auto-hold at a standstill (p. 411)
Brakes (p. 403)
Parking brake (p. 406)
Hill Start Assist (p. 411)

STARTING AND DRIVING
411
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. 410)
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. 410)
Brakes (p. 403)

STARTING AND DRIVING
* Option/accessory.
412
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. 328)
BLIS
* (p. 329)
Brake functions (p. 403)
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 and an electric motor for rear-wheeldrive. The number of gears allows the engine'storque and power band to be effectively uti-lized. Two of the gears are overdrive gears thatsave fuel when driving at a constant enginespeed. Manual shifting is also possible. Theinstrument panel shows the gear currently inuse.
Related information
Automatic transmission (p. 412)
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.
Overview of gear selector and gear shift pattern in the instrument panel
The instrument panel shows which gear is cur- rently in use: R , N , D or B. P position is electric.
For manual shifting, the gear indicator in the instrument panel displays the gear currentlybeing used.
4 Hill Start Assist

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* Option/accessory.415
Brake - B
Brake position in instrument panel overview.
From the B position, it is possible to shift
manually. B can be selected at any time while
driving. When the accelerator pedal is released, the electric motor brakes the vehicleand the hybrid battery is recharged at thesame time. This offers additional opportunitiesto recharge the hybrid battery, since the bat-tery is charged even when the brake pedal isnot depressed. Select brake by moving the gear selector rear- ward from the D position. The currently
selected gear will be displayed in the instru-ment panel.
Push the gear selector to the right toward"
+ " (plus) and release to shift up one gear.
Push the gear selector to the left toward"
– " (minus) and release to shift down one
gear.
Push the gear selector rearward to returnto
D mode.
For smooth shifting and engine performance,the transmission will shift down automaticallyif the vehicle's speed becomes too low for theselected gear.
Related information
Automatic transmission (p. 412)
Shiftlock (p. 416)
Using the steering wheel paddles
* to shift
(p. 415)
The kickdown function (p. 417)
Using the steering wheel paddles
*
to shift
The steering wheel paddles are a supplement to the gear selector and make it possible toshift manually without removing your handsfrom the steering wheel.
" -": Shift down one gear.
" + ": Shift up one gear.
Activating the steering wheel paddlesIn order to shift gears using the paddles, they must first be activated:
–Pull one of the paddles toward the steer- ing wheel.
> A number in the instrument panel indi-
cates the current gear being used.

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419
Starting and stopping the combustion engine in Twin Enginevehicles An advanced control system determines the distance that the vehicle can be driven on thecombustion engine, electric motor, or both atthe same time. When driving on only theelectric motor, the vehicle may automaticallystart the combustion engine due to outsidecircumstances, e.g. low ambient tempera-tures. This is completely normal. The com-bustion engine will also always start whenthe hybrid battery is nearly fully discharged.
Climate settings at low temperaturesAt low ambient temperatures, the combustion engine will sometimes start automatically tohelp achieve the desired passenger compart-ment temperature and air quality. The amountof time the combustion engine is running canbe affected by lowering the temperature
reducing blower speed
activating
Pure drive mode.
Using the electric motor in hot or cold
weather
At very low or high ambient temperatures, the electric motor's driving range and power maybe reduced and affect how often the combus-tion engine automatically starts.
Emission control systemTo help ensure that the emission control sys-tem is as energy-efficient as possible, thecombustion engine will run for several minutesafter it is started. The amount of time the com-bustion engine needs to be used variesdepending on the temperature of the three-way catalytic converter.
WARNING
California Proposition 65 Operating, servicing and maintaining a pas- senger vehicle can expose you to chemi-cals including engine exhaust, carbon mon-oxide, phthalates, and lead, which areknown to the State of California to causecancer and birth defects or other reproduc-tive harm. To minimize exposure, avoidbreathing exhaust, do not idle the engineexcept as necessary, service your vehicle ina well ventilated area and wear gloves orwash your hands frequently when servicingyour vehicle. For more information go towww.P65Warnings.ca.gov/passenger-vehicle.
Related information
Drive systems (p. 418)
Economical driving (p. 428)
Drive modes (p. 419)
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. Each drive mode is adaptedto help optimize driving characteristics. Steering
Engine/transmission/all-wheel drive
Brakes
Shock absorbers
Instrument panel
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 modes
WARNING
Keep in mind that the vehicle does not emit any engine noise when using the electricmotor and may therefore be difficult todetect for children, pedestrians, cyclists oranimals. This is particularly true at lowspeeds, e.g. in parking lots.

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* Option/accessory.429
Driving
Choose the Pure drive mode to help mini-
mize electric power consumption.
Maintain a steady speed and a generous following distance to traffic ahead to mini-mize braking. This drive mode has thelowest power consumption.
Balance energy requirements using theaccelerator pedal. Use the indicator on theinstrument panel to see available electricpower and avoid starting the combustionengine unnecessarily. The electric motor ismore effective than the combustionengine, especially at low speeds.
When braking is necessary, brake gentlyusing the brake pedal. This will helprecharge the hybrid battery. A regenerativefunction is integrated in the brake pedaland can be augmented by the electricmotor's braking capacity when the gearselector is in mode
B.
Higher speeds increase energy consump-tion - air resistance increases with speed.
Activate the
Hold function in the Function
view at high speeds when traveling farther than is possible using the hybrid battery'scapacity.
Whenever possible, avoid using the
Charge function to charge the hybrid bat-
tery. Charging the battery using the com- bustion engine increases fuel consump- tion and carbon dioxide emissions.
In a cold climate, reduce heating of thewindshield/rear window, mirrors, seatsand the steering wheel.
Maintain the correct pressure in the tiresand check pressure regularly.
The type of tires used could affect energyconsumption - consult a retailer for adviceon suitable tires.
Remove unnecessary items from the vehi-cle - the heavier the load, the higher thefuel consumption.
Roof loads increase air resistance andincrease fuel consumption. Remove roofboxes, ski racks, etc. that are not in use.
Avoid driving with the windows open.
Do not keep the vehicle still on an upwardgradient by using the accelerator pedal.Use the brakes instead.
Related information
Drive-E
‒ purer driving pleasure (p. 28)
Energy distribution in hybrid mode using map data
* (p. 424)
Factors affecting electric motor range (p. 429)
Hybrid gauge (p. 83)
Checking tire pressure (p. 527)
Factors affecting electric motor range
A number of factors affect the electric motor's driving range. The ability to achieve along driving range varies according to theoutside conditions and to how the vehicle isdriven.
The certified value for the distance that can be driven using the electric motor should not beconsidered an expected driving range. Theactual range is dependent on a number of fac-tors.
Factors affecting driving rangeThe driver can influence some factors affectingdriving range, but not all. The longest range is achieved under very favorable conditions when all factors positivelyinfluence range.

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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.
To help prevent damage to the vehicle when driving through water:
Do not drive in water higher than the floorof the vehicle. If possible, check the depthof the water at its deepest point beforedriving through it. Be particularly carefulwhen driving through flowing water.
Do not drive faster than walking speed.
Do not stop the vehicle in the water. Drivecarefully forward or back the vehicle out ofthe water.
Remember that waves created by passingvehicles could cause the water level to riseabove the vehicle's floor level.
Avoid driving through salt water to helpavoid the risk of corrosion.
CAUTION
Parts of the vehicle (e.g. engine, transmis- sion, driveline, electrical components, etc.)can be damaged if the vehicle is driventhrough water higher than its floor level.Damage to any components caused byflooding, vapor lock or insufficient oil is notcovered under warranty. If the engine stalls while the vehicle is in water, do not attempt to restart it. Havethe vehicle towed on the bed of a towtruck to a workshop - an authorized Volvoworkshop is recommended.
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.
When you have passed the water, press lightly on the brake pedal and check that the brakesare functioning properly. Water, mud, slush,etc. can make the brake linings slippery,resulting in delayed braking effect. If the vehicle is equipped with a trailer cou- pling contact, clean the contact after driving inwater or mud.
Related information
Recovery (p. 444)

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WHEELS AND TIRES
542
CAUTION
Snow chains can be used on the vehicle, with the following restrictions:
Always follow the manufacturer'sinstallation instructions carefully. Installchains as tightly as possible andretighten periodically.
Only put snow chains on the frontwheels (also applies to all-wheel drivevehicles).
If accessory, aftermarket or "custom"tires and wheels with different dimen-sions than the original tires and wheelsare used, snow chains in some casesmay NOT be used. Sufficient distancebetween the chains and brakes, sus-pension and body components mustbe maintained.
Check local regulations regarding theuse of snow chains before installing.
Never exceed the snow chain manu-facturer's specified maximum speedlimit. Under no circumstances shouldyou exceed 50 km/h (30 mph).
Avoid bumps, holes or sharp turnswhen driving with snow chains.
Avoid driving on surfaces withoutsnow as this wears out both the snowchains and the tires.
The handling of the vehicle can be adversely affected when driving withchains. Avoid fast or sharp turns aswell as locked wheel braking.
Some types of strap-on chains affectbrake components and therefore mustNOT be used.
Consult a Volvo retailer for more information about snow chains.
Related information
Winter driving (p. 432)
Tire sealing system 14
The temporary tire sealing system can be used to seal a puncture in a tire or to checkand adjust the pressure in the tire. Models equipped with a spare wheel 15
do not
have the tire sealing system.
WARNING
California Proposition 65 Operating, servicing and maintaining a pas- senger vehicle can expose you to chemi-cals including engine exhaust, carbon mon-oxide, phthalates, and lead, which areknown to the State of California to causecancer and birth defects or other reproduc-tive harm. To minimize exposure, avoidbreathing exhaust, do not idle the engineexcept as necessary, service your vehicle ina well ventilated area and wear gloves orwash your hands frequently when servicingyour vehicle. For more information go towww.P65Warnings.ca.gov/passenger-vehicle.
The tire sealing system consists of a compres- sor and a bottle containing sealing compound.The sealing functions as a temporary repair.