brake VOLVO S90 TWIN ENGINE 2020 Repair Manual

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HYBRID INFORMATION
382
Charging cable handle and charging socket.
Charging status is indicated in three ways:
The indicator lights in the charging module (the unit connected to the wall outlet).
Indicator light in the vehicle's chargingsocket.
Images and text in the instrument panel.
The start battery is charged while the hybridbattery is charging and stops charging whenthe hybrid battery is fully charged. If the hybrid battery's temperature is below -10 ºC (14 ºF) or above 40 ºC (104 ºF), some
of the vehicle's functions may be reduced ornot available at all. The electric motor cannot be used if the bat- tery's temperature is too low or too high. If thePURE drive mode is selected, the gasolineengine will start.
Charging using the gasoline engine
The vehicle generates electrical current to charge the battery, e.g. when the driver lightly presses the brakepedal or when engine braking is used on down-grades.
The vehicle can also generate current to the hybrid battery to charge it. The hybrid battery can also be recharged by lightly depressing the brake pedal, i.e.during light braking. This converts thevehicle's kinetic energy to electricalenergy, which is used to charge the hybridbattery.
In gear position
B, the electric motor
brakes the vehicle when the acceleratorpedal is released and the hybrid battery isrecharged at the same time.
The combustion engine can also helprecharge the hybrid battery.
Related information
Charge cable (p. 383)
Charging current (p. 383)
Opening and closing the charging socketcover (p. 386)
Initiating hybrid battery charging (p. 386)
Stopping hybrid battery charging (p. 392)
Charging status in the charging cable'scharging module (p. 389)
Charging status in the vehicle's chargingsocket (p. 388)
Charging status in the instrument panel(p. 390)
Twin Engine symbols and messages in theinstrument panel (p. 394)
Automatic transmission (p. 412)
Changing drive mode (p. 423)
Long-term storage of vehicles with hybridbatteries (p. 396)

HYBRID INFORMATION
391
NOTE
If the instrument panel is not used, it will go dark after a period of time. To reactivatethe display: depress the brake pedal,
open one of the doors, or
put the ignition in mode
I by turning
the START knob clockwise and then
releasing.
Related information
Charging the hybrid battery (p. 381)
Twin Engine symbols and messages in the instrument panel (p. 394)
Charging status in the vehicle's chargingsocket (p. 388)
Charging status in the charging cable'scharging module (p. 389)
Stopping hybrid battery charging (p. 392)

STARTING AND DRIVING
* Option/accessory.
398
Starting the vehicle
The vehicle can be started using the start knob in the tunnel console when the remotekey is in the passenger compartment.
Start knob in the tunnel console.
WARNING
Before starting:
Buckle your seat belt.
Adjust the seat, steering wheel and mirrors.
Make sure you can fully depress thebrake pedal.
The remote key is not physically used to startthe ignition because the vehicle is equippedwith the keyless Passive Start system. To start the vehicle:
CAUTION
The vehicle cannot be started if the charg- ing cable is still plugged in. Make sure topull out the charging cable from the charg-ing socket before starting the vehicle.
1. The remote key must be inside the vehicle.
For vehicles with Passive Start, the key must be in the front section of the passen-ger compartment. With the optional key- less locking/unlocking function *, the key
can be anywhere in the vehicle.
2. Press and hold down the brake pedal 1
as
far as possible.
3. Turn the start knob clockwise and release. The control will automatically return to the original position.
WARNING
Never use more than one inlay mat at a time on the driver's floor. If any othertype of floor mat is used, remove theoriginal mat from the driver's seat floorbefore driving. All types of mats mustbe securely anchored in the attach-ment points in the floor. Make sure thefloor mat does not impede the move-ment of the brake pedal or acceleratorpedal in any way, as this could be aserious safety hazard.
Volvo's floor mats are specially manu-factured for your vehicle. They must beproperly secured in the attachmentpoints in the floor to help ensure theycannot slide and become trappedunder the pedals.
The starter motor will crank until the enginestarts or until overheating protection is trig-gered. During normal start conditions, the vehicle's electric motor will be prioritized and the gaso-line engine will remain off. This means thatonce the start knob is turned clockwise, theelectric motor has been "started" and the vehi-cle is ready to be driven. The warning andinformation symbols in the instrument panel
1 If the vehicle is moving, it is only necessary to turn the start knob clockwise to start the engine.

STARTING AND DRIVING
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399
will go out and the selected theme will be dis- played to indicate that the electric motor isactivated. In some situations, such as in cold weather or if the hybrid battery's charge level is too low,the gasoline engine will start instead.
Error messagesIf the Vehicle key not found message is
shown in the instrument panel at start, place the remote key at the backup reader and thenmake a new start attempt.
Location of the backup reader in the tunnel console.
NOTE
When the remote key is placed in the backup reader, make sure that no othervehicle keys, metal objects or electronicdevices (e.g. cellular phones, tablets, lap-tops or chargers) are in the backup reader.Multiple vehicle keys close to each other inthe backup reader can disrupt their func-tionality.
If Vehicle start System check, wait is dis-
played in the instrument panel while attempt- ing to start the vehicle, wait until the messagedisappears and try again to start the vehicle.
CAUTION
If the engine has not responded after 3 attempts – wait for 3 minutes before star-ting a new attempt. Starting capabilityincreases if the starter battery is given timeto recover.
NOTE
The vehicle cannot be started if the hybrid battery is discharged.
WARNING
Never remove the remote control key from
the vehicle while driving.
WARNING
Always remove the remote key from the passenger compartment when youleave the vehicle and make sure theignition is in mode
0.
Always put the gear selector in
P and
apply the parking brake before leavingthe vehicle. Never leave the vehicleunsupervised while the engine is run-ning.
Always open the garage door fully andmake sure that ventilation is very goodbefore starting the engine in a garage.The exhaust fumes produced by thevehicle contain carbon monoxide,which is invisible and odorless but verytoxic.

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STARTING AND DRIVING
402
Mode FunctionsII The headlights illuminate.
Warning/indicator lights illumi- nate for 5 seconds.
A number of other systems areactivated. However, seat andrear window heating can onlybe activated when the engineis running.
This ignition mode uses a lot ofcurrent from the battery andshould be avoided wheneverpossible!
A Also activated when the door is opened.
Related information
Starting the vehicle (p. 398)
Adjusting the steering wheel (p. 195)
Jump starting using another battery (p. 441)
Selecting ignition mode (p. 402)
Selecting ignition mode
The vehicle's ignition can be put in various modes (levels) to make different functionsavailable.
Selecting an ignition mode
Start knob in the tunnel console.
Ignition mode 0
– Unlock the vehicle and
keep the remote key in the passenger compartment.
NOTE
To set level I or II without engine start –
do not depress the brake pedal (or clutch
pedal for vehicles with manual transmis- sion) when selecting this ignition mode.
Ignition mode I
– Turn the start knob
clockwise and release it. The control will automatically return to the original posi- tion.
Ignition mode II
– Turn the start knob
clockwise and hold it there forapprox. 5 seconds. Release the knob,which will automatically return to its origi-nal position.
Back to ignition mode 0
– To return to
ignition mode 0 from modes I and II, turn
the start knob clockwise and release it.The control will automatically return to theoriginal position.
Related information
Starting the vehicle (p. 398)
Switching off the vehicle (p. 400)
Ignition modes (p. 401)
Adjusting the steering wheel (p. 195)
Jump starting using another battery(p. 441)

STARTING AND DRIVING
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403
Brake functions
The vehicle's brakes are used to reduce speed or prevent the vehicle from rolling.
In addition to the wheel brakes and parking brakes, the vehicle is also equipped with anumber of automatic brake assist functions.These systems provide assistance by e.g. thedriver not needing to depress the brake pedalat a traffic light or when starting up a hill. Depending on how the vehicle is equipped, the following brake assist functions may beincluded:
Auto-hold brake function at a standstill(Auto Hold)
Hill Start Assist (Hill Start Assist)
Braking assist after a collision
City Safety
Related information
Brakes (p. 403)
Parking brake (p. 406)
Auto-hold brakes (p. 410)
Braking assist after a collision (p. 412)
Hill Start Assist (p. 411)
City Safety
™ (p. 314)
Brakes
The brake pedal is used to apply the vehicle's regular brakes, which are part of the brakesystem.
The vehicle is equipped with two brake cir- cuits. If one brake circuit is damaged, thebrake pedal will go down further whendepressed. More pressure will then berequired from the driver for normal brakingeffect.
WARNING
The power brakes only work when the electric motor or combustion engine is run-ning.
If the brake pedal is used when the engine is switched off, greater pressure must be appliedto brake the vehicle. In very hilly areas or when driving with a heavy load, gear position B can be used to augment
the brakes with engine braking.
Anti-lock brakesThe vehicle is equipped with an Anti-lock Braking System (ABS 2
), which helps prevent
the wheels from locking and helps maintain steering control when braking. Vibrations maybe felt from the brake pedal when ABS isoperating, which is normal. After the vehicle is started, a brief test of theABS system is automatically performed whenthe driver releases the brake pedal. An addi-tional automatic test of the system may beperformed when the vehicle is traveling at alow speed. During the test, the brake pedalmay feel as though it is pulsating.
Light braking charges the hybrid
battery
When the brakes are applied lightly, the elec-tric motor braking function is used. This con-verts the vehicle's kinetic energy into electricalenergy, which is used to charge the hybridbattery. When the battery is being chargedwith the electric motor braking function, thiswill be indicated in the instrument panel.
2 Anti-lock Braking System

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STARTING AND DRIVING
404
When the battery is being charged with the electric motor braking function, this will be indicated in theinstrument panel.
This function is active at speeds in the range of 150-5 km/h (93-3 mph). When braking atspeeds outside of this range, or during harderbraking, the hydraulic braking system is usedto augment braking. This is indicated in theinstrument panel with the pointer down in thered area.
Symbols in the instrument panel
Symbol Meaning
A
BCheck the brake fluid level. If the level is low, fill brake fluid andcheck to determine the reasonfor the loss of brake fluid.
A
BFault in pedal sensor.
Symbol Meaning
A
B
Steady glow for 2 seconds after the engine is started: Automaticfunction check. Steady glow for more than 2 seconds: Fault in the ABS sys-tem. The vehicle's regular brakesystem is still working, but with-out the ABS function.
If the message Brake pedal
Characteristics changed Serv- ice required
is displayed, the
"Brake-by-wire" system is not functioning properly. Greaterpressure will be required to brakethe vehicle.
A In Canada.
B In the US.

STARTING AND DRIVING
405
WARNING
If the warning symbols for both brake fault and ABS fault are lit simultaneously, theremay be a fault in the brake system.
If the brake fluid reservoir level is nor- mal when this occurs, drive carefully tothe nearest workshop to have thebrake system checked - an authorizedVolvo workshop is recommended.
If the brake fluid has fallen below theMIN
level in the brake fluid reservoir,
the vehicle should not be driven untilthe brake fluid has been filled. The rea-son for the brake fluid loss must bechecked.
Related information
Brake Assist System (p. 405)
Auto-hold brakes (p. 410)
Hill Start Assist (p. 411)
Braking on wet roads (p. 405)
Braking on salted roads (p. 406)
Maintenance of the brake system(p. 406)
Brake lights (p. 158)
Brake Assist System The brake enhancing system, (BAS 3
), helps
increase braking force and can thereby reduce braking distance.
The system monitors the driver's braking hab- its and increases braking force when neces-sary. Braking force can be increased up to thepoint at which the ABS intervenes. The func-tion is deactivated when pressure on the brakepedal is decreased.
Related information
Brakes (p. 403)
Braking on wet roads
Prolonged driving in heavy rain without brak- ing may cause braking effect to be slightlydelayed the first time the brakes are applied.
This may also occur after washing the vehicle. It will then be necessary to apply greater pres-sure to the brake pedal. You should thereforemaintain a greater distance to the vehicleahead. Firmly apply the brakes after washing the vehicle or driving on wet roads. This helpswarm up the brake discs, enabling them to drymore quickly and protecting them against cor-rosion. Consider the current traffic situationwhen braking.
Related information
Brakes (p. 403)
Braking on salted roads (p. 406)
3
Brake Assist System

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.

STARTING AND DRIVING
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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.