2020 VOLVO S90 TWIN ENGINE battery

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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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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.

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Parking on a hillAlways use the parking brake when parking on a hill.
WARNING
Always apply the parking brake when park- ing on an incline. Selecting a gear or put-ting the automatic transmission in P may
not be sufficient to keep the vehicle sta-tionary in all situations.
If the vehicle is pointing uphill:
Turn the front wheels so they are pointing away from
the curb.
If the vehicle is pointing downhill:
Turn the front wheels so they are pointingtoward
the curb.
Heavy load uphill
Heavy loads, such as a trailer, could cause the vehicle to roll backward when the parkingbrake is released automatically on steep uphillgradients. To help avoid this, pull the controlupward while you are driving away. Releasethe control when the vehicle gains traction.
Related information
Activating and deactivating the parkingbrake (p. 407)
Parking brake malfunction
If you are unable to deactivate or activate the parking brake after several attempts, contactan authorized Volvo workshop.
A audible warning signal will sound if the park- ing brake is activated while the vehicle isbeing driven. If the vehicle must be parked before the prob- lem is rectified, turn the wheels as when park-ing on an incline and put the gear selector inP .
Low battery charge levelIf the battery charge level is too low, it will notbe possible to activate or deactivate the park-ing brake. Connect an auxiliary battery to thevehicle if the battery is discharged.
Replacing brake padsDue to the design of the electric parkingbrake, the rear brake pads must be replacedby a workshop. An authorized Volvo workshopis recommended.
Symbols in the instrument panel
Symbol Meaning
A
B A flashing symbol indicates that a fault has been detected. Seethe message in the instrumentpanel.
A
BFault in the brake system. See the message in the instrumentpanel.
Information message in the instrument panel.
A
Canadian models.
B US models.

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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)

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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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Drive systemsVolvo Twin Engine combines a combustion engine for the front wheels and an electricmotor for the rear wheels.
Two drive systemsDepending on the selected drive mode and power available in the electric motor, the drivesystems can either be used separately or intandem. The electric motor gets its energy from a hybrid battery located under the tunnel con-sole. The hybrid can be charged from a walloutlet or in a special charging station. Thecombustion engine can also charge the hybridbattery using a special high-voltage generator. Both the combustion engine and the electric motor can generate power directly to thewheels. An advanced control system coordi-nates both the drive systems to help optimizedriving economy.
Hybrid battery - The hybrid battery's func- tion is to store electrical current. Thisenergy is provided by plugging the charg-ing cable into an electrical outlet, throughregenerative braking or from the high-volt-age generator. This provides current topower the electric motor and to temporar-ily power the electrical air conditioning toprecondition the passenger compartment.
Combustion engine - The combustion engine starts when the charge level in thehybrid battery is too low to provide thepower output requested by the driver.
High-voltage generator 6
- Charges the
hybrid battery. Starter for the combustion engine. Can provide the combustion engine with extra electrical current.
Electric motor - Powers the vehicle using electricity. Can provide extra torque andpower during acceleration. Provides elec-trical all-wheel drive functionality. Regen-erates braking energy into electrical cur-rent.
Related information

General information about Twin Engine(p. 380)
Starting and stopping the combustionengine in Twin Engine vehicles (p. 419)
Drive modes (p. 419)
Transmission (p. 412)
Factors affecting electric motor range(p. 429)
6
CISG (Crank Integrated Starter Generator) – combined high-voltage generator and starter.

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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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WARNING
Do not leave the vehicle in an unventilated area with a drive mode activated and thecombustion engine switched off. Theengine will start automatically if the chargelevel in the hybrid battery is low and theresulting exhaust gases can be very harm-ful to people and animals.
Hybrid
This is the default mode in which the elec- tric motor and combustion engine worktogether.
The vehicle starts in
Hybrid mode. The control
system uses both the electric motor and the gasoline engine – separately or in tandem –and adapts utilization with regard to perform-ance, fuel consumption and comfort. Drivingcapacity on the electric motor alone is deter-mined by factors such as the hybrid battery'scharge level, the need for heat or cooling inthe passenger compartment, etc. If there is sufficient charge in the battery, it is possible to drive solely on electric power.When the accelerator pedal is pressed, onlythe electric motor will be activated until thebattery reaches a certain charge level. Abovethis level, the current in the battery cannotsupply the power requested by the acceleratorpedal and the combustion engine will start. When the hybrid battery's charge level is low, the combustion engine will start more fre- quently to save the remaining current in thebattery. Charge the hybrid battery from a120-240 volt outlet using a charging cable, or activate
Charge in Function view to reset the
option of only using the electric motor. This drive mode is designed for low energy consumption with a mix between the electricmotor and gasoline engine, without compro-mising on climate comfort or driving experi-ence. When faster acceleration is requestedby the driver, the electric driveline will be uti-lized to help provide maximum additionalpower. The vehicle also monitors the driving condi- tions and automatically engages all-wheeldrive if necessary. All-wheel drive and extraelectric power are always available regardlessof the battery's charging status.
Information in the instrument panel
When driving in Hybrid mode, a hybrid gauge will be displayed in the instrument panel. Thegauge will indicate the amount of electricalcurrent required when the driver depressesthe accelerator pedal. The marker between thelightning and the drop shows how much cur-rent is available.
The instrument panel gauge when both the electric motor and the combustion engine are being used.
The instrument panel also shows how much current is being restoredto the battery (regenerated) duringlight braking.