2018 VOLVO XC90 T8 engine

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* Option/accessory.
438
Related information
• Rear Collision Warning (p. 347)
• BLIS
* (p. 348)
• Brake functions (p. 429)
Transmission The transmission is part of the vehicle's driveline (power transmission) between the engine andthe drive wheels. The function of the transmis-sion is to change gears depending on speedand power needs.
The vehicle has an 8-speed automatic transmis- sion and an electric motor for rear-wheel drive.The number of gears allows the engine's torqueand power band to be effectively utilized. Two ofthe gears are overdrive gears that save fuel whendriving at a constant engine speed. The steering wheel paddles
* can be used to shift up or down
manually. The instrument panel shows the gear currently in use.
CAUTION
Check the operating temperature of the transmission to help avoid damage to any ofthe drive system components. If there is a riskof overheating, a warning symbol will appearin the instrument panel and a text messagewill be displayed. Follow the recommenda-tions given.
Symbols in the instrument panelIf a problem should occur with the transmission, a symbol and a message will appear in the instru-ment panel.
SymbolMeaning
Information and messages related to the transmission. Follow the rec-ommendations provided.
Hot or overheated transmission. Follow the recommendations provi-ded.
Reduced performance/Acceler-
ation performance reduced
In the event of a temporary fault in the driveline, the vehicle may gointo a "limp home" mode withreduced power output to help avoiddamage to the driveline.
Related information
• Gear selector positions for automatic trans- missions (p. 439)
• Gear indicator
* (p. 442)

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439
Gear selector positions forautomatic transmissions In vehicles with an automatic transmission, the system selects the optimal gear for the currentdriving conditions. The transmission also has amanual mode.
The instrument panel shows which gear is cur- rently in use:
P, R, N, D or B.
For manual shifting, the gear indicator in the instrument panel displays the gear currentlybeing used (1-8).
Selecting gearsThe gear selector is a shift-by-wire selector,where shifting is done electronically instead ofmechanically. This makes shifting easier and thegear positions more distinct. Select gears by moving the spring-loaded, non-locking gear selector forward or backward.
Gear selector positions
Park -
P
Park is activated using the P button located next
to the gear selector. Select
P when the vehicle is parked or when star-
ting the engine. The vehicle must be stationary when Park is selected. To move to another gear from Park, the brake pedal must be depressed and the ignition in mode II.
When parking – apply the parking brake before shifting to Park.
WARNING
Always apply the parking brake when parking on an incline. Selecting a gear or putting the automatic transmission in P may not be suffi-
cient to keep the vehicle stationary in all sit- uations.
NOTE
The gear selector must be in the P position
before the vehicle can be locked and the alarm set.

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* Option/accessory.
440 Help functions The system will automatically shift to
P:
• if the ignition is switched off while
D or R is
selected.
• if the driver unbuckles the seat belt and opens the driver's door while the vehicle isrunning with the gear selector in a gear other than
P.
To park a vehicle with an unbuckled seat belt andopen door – end P mode by shifting to R or D
again.
Reverse - R
Select R when backing up. The vehicle must be
stationary when Reverse is selected.
Neutral - N
No gear is selected and the engine can be started. Apply the parking brake if the vehicle is stationary with the gear selector in N.
To move the gear selector from Neutral to another gear, the brake pedal must be depressed and the ignition in mode II.
D drive mode
D is the normal driving gear position. The trans-
mission shifts up or down automatically depend- ing on acceleration and speed. The vehicle mustbe stationary when the gear selector is moved from R to D.
Brake - B
B can be selected at any time during a drive. In B
mode, the engine braking function is activated when the accelerator pedal is released, whichhelps charge the hybrid battery. This offers addi-tional opportunities to recharge the hybrid bat-tery, since the battery is charged even when thebrake pedal is not depressed.
B mode in the instrument panel.
From B mode, it is possible to manually shift to
lower gears. The currently selected gear (1-8) will be displayed in the instrument panel.
• Pull the gear selector backward once to shiftdown one gear.
• Pull the gear selector backward again to shiftdown to lower gears.
To shift manually to a higher gear, the vehicle must be equipped with steering wheel paddles *. •
Push the gear selector forward to return to
D
mode.
For smooth shifting and engine performance, the
transmission will shift down automatically if the vehicle's speed becomes too low for the selectedgear.
Related information
• Shiftlock (p. 442)
• Using the steering wheel paddles
* to shift
(p. 441)
• The kickdown function (p. 442)
• Gear indicator
* (p. 442)

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* Option/accessory.441
Using the steering wheel paddles *to shift
The steering wheel paddles are a supplement to the gear selector and make it possible to shiftmanually without removing your hands from thesteering wheel.
Activating the steering wheel paddlesIn order to shift gears using the paddles, they must first be activated:
–Pull one of the paddles toward the steering wheel.
> A number in the instrument panel indi- cates the current gear being used.
Instrument panel when the paddles are activated for shifting.
ChangeTo shift one gear:
–Pull one of the paddles toward the steering wheel and then release.
"-": Shift down one gear.
" + ": Shift up one gear.
As long as the engine speed (rpm) is within the permissible range for the selected gear, a gearshift will take place each time a paddle is pulled. After each gear shift, a number indicating the current gear will be displayed in the instrumentpanel.
Turning off Start/Stop
Manual deactivation in gear D and B
–Deactivate the paddles by pulling the right paddle ( +) toward the steering wheel and
holding it until the number of the current gear is no longer displayed in the instrumentpanel. > The transmission will revert to gear D or B
depending on which gear was selected before the paddles were activated.
Automatic deactivation
In gear position D, the steering wheel paddles
are deactivated after a short period of time if they are not used. The number of the current gear willno longer be displayed in the instrument panel. In gear position B, the paddles will not activate
automatically.
Related information
• Gear selector positions for automatic trans- missions (p. 439)
• Gear indicator
* (p. 442)

STARTING AND DRIVING
* Option/accessory.
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Shiftlock The automatic transmission's shiftlock function helps prevent inadvertently moving the gearselector between different positions.
Automatic shiftlockThe automatic shiftlock has a separate safety system.
From Park - P
To move the gear selector from the P position,
the brake pedal must be depressed and the igni- tion in mode II.
From Neutral - N
If the gear selector is in N and the vehicle has
been stationary for at least 3 seconds (with or without the engine running), the gear selector willbe locked in that position. To move the gear selector from N to another
gear, the brake pedal must be depressed and the ignition in mode II.
Messages in the instrument panelIf the gear selector is locked in position, a mes- sage will appear in the instrument panel, e.g.
Gear lever Press brake pedal to activate
gear lever.
There is no mechanical shiftlock function.
Related information
• Gear selector positions for automatic trans- missions (p. 439)
The kickdown function
Kickdown is used when maximum acceleration is needed, e.g. when passing.
When the accelerator pedal is depressed all the way to the floor (past the normal full acceleratorposition), the transmission will automaticallyengage kickdown, i.e. immediately shift down to alower gear. If the accelerator pedal is released from the kick- down position, the transmission will automaticallyshift up again.
Safety function
The transmission control module is equipped with a downshift protection feature to help prevent theengine from overheating. In some conditions, the transmission will prevent downshifting/kickdown if this would lead to suchhigh engine speed (rpm) that the engine couldbe damaged. If the driver still attempts downshift-ing or kickdown at a high rpm, nothing will hap-pen and the original gear will remain selected. With kickdown, the vehicle can downshift one or more steps at a time depending on the enginespeed. The vehicle upshifts when the engine rea-ches its maximum rpm to prevent engine dam-age.
Related information
• Gear selector positions for automatic trans-missions (p. 439)
Gear indicator
*
The gear indicator in the instrument panel shows the gear currently being used for manual shiftingand indicates when another gear should beselected to optimize fuel economy.
For eco-friendly driving when manually shifting, it is important to use the correct gear and to shiftgears in good time. The gear indicator in the instrument panel shows the gear currently being used and indicates withan upward-facing arrow if a higher gear shouldbe selected. The gear indicator is shown in gear B .
Gear indicator in instrument panel 2
.
Related information
• Gear selector positions for automatic trans- missions (p. 439)

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443
All Wheel Drive (AWD)All-wheel drive, All Wheel Drive (AWD), also called four-wheel drive, means that power is dis-tributed to all four wheels, which improves trac-tion.
The electric motor that powers the rear wheels enables electronic all-wheel drive functionality. To achieve the best traction, power is automati- cally directed to the wheels that have the bestgrip. The system continuously calculates theneed for torque to the rear wheels, and canimmediately redistribute up to half of the engine'storque to the rear wheels. All-wheel drive also has a stabilizing effect at higher speeds. In normal driving conditions, mostof the engine's power is directed to the frontwheels. When the vehicle is stationary, all-wheeldrive is always activated in preparation for maxi-mum traction during acceleration. All-wheel drive reacts differently depending on which drive mode is selected.
Related information
• Drive modes (p. 445)
• Low Speed Control (p. 453)
• Transmission (p. 438)
Drive systems
Volvo Twin Engine combines a combustion engine for the front wheels and an electric motorfor 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 in tan-dem. The electric motor gets its energy from a hybrid battery located under the tunnel console. Thehybrid can be charged from a wall outlet or in a special charging station. The combustion engine can also charge the hybrid battery using a special high-voltage generator. Both the combustion engine and the electric motor can generate power directly to the wheels.An advanced control system coordinates both thedrive systems to help optimize driving economy.
Hybrid battery - The hybrid battery's function is to store electrical current. This energy isprovided by plugging the charging cable intoan electrical outlet, through regenerativebraking or from the high-voltage generator.This provides current to power the electricmotor and to temporarily power the electricalair conditioning to precondition the passen-ger compartment.
Combustion engine - The combustion engine starts when the charge level in the hybridbattery is too low to provide the power outputrequested by the driver.
High-voltage generator 3
- Charges the hybrid
battery. Starter for the combustion engine.
2 This illustration is generic. The layout may vary depending on vehicle model and software updates.
3 CISG (Crank Integrated Starter Generator) - Combined high-voltage generator and starter.

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444Can provide the combustion engine with extra electrical current.
Electric motor - Powers the vehicle using electricity. Can provide extra torque andpower during acceleration. Provides electricalall-wheel drive functionality. Regeneratesbraking energy into electrical current.
Related information
•
General information about Twin Engine(p. 406)
• Starting and stopping the combustion enginein Twin Engine vehicles (p. 444)
• Drive modes (p. 445)
• Transmission (p. 438)
• Factors affecting electric motor range(p. 458)
Starting and stopping thecombustion engine in Twin Enginevehicles
An advanced control system determines the dis- tance that the vehicle can be driven on the com-bustion engine, electric motor, or both at thesame time. When driving on only the electricmotor, the vehicle may automatically start thecombustion engine due to outside circumstan-ces, e.g. low ambient temperatures. This is com-pletely normal. The combustion engine will alsoalways start when the hybrid battery is nearlyfully discharged.
Climate settings at low temperaturesAt low ambient temperatures, the combustion engine will sometimes start automatically to helpachieve the desired passenger compartmenttemperature and air quality. The amount of timethe combustion engine is running can be affec-ted 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 may bereduced and affect how often the combustionengine automatically starts.
Emission control systemTo help ensure that the emission control systemfunctions optimally, the combustion engine willrun for several minutes after it is started. Theamount of time the combustion engine needs tobe used varies depending on the temperature ofthe three-way catalytic converter.
Related information
•
Drive systems (p. 443)
• Economical driving (p. 456)
• Using the electric motor only (p. 457)
• Drive modes (p. 445)

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Drive modes
Drive modes affect the vehicle's driving charac- teristics in different ways to enhance and sim-plify the driving experience in certain types of sit-uations.
Drive modes enable easy access to the vehicle's many functions and settings in different drivingsituations. The following systems are adapted tohelp optimize driving characteristics in each drivemode: • Steering
• Engine/transmission/all-wheel drive
• Brakes
• Pneumatic suspension
* and shock absorbers
• Instrument panel
• Climate control settings
Select the drive mode that is best suited to the current driving conditions. Keep in mind that notall drive modes are available in all situations.
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 to detectfor children, pedestrians, cyclists or animals.This is particularly true at low speeds, e.g. inparking lots.
WARNING
Do not leave the vehicle in an unventilated area with a drive mode activated and the com-bustion engine switched off. The engine willstart automatically if the charge level in thehybrid battery is low and the resulting exhaustgases can be very harmful to people and ani-mals.
HYBRID
• This is the default mode in which the electric motor and combustion engine work together.
The vehicle starts in Hybrid mode. The control system uses both the electric motor and the gas-oline engine - separately or in tandem - and cal-culates optimal utilization with regard to perform-ance, fuel consumption and comfort. At highspeeds, ground clearance is automatically low- ered 4
to reduce air resistance. Driving capacity on
the electric motor alone is determined by factors such as the hybrid battery's charge level, the need for heat/cooling in the passenger compart-ment, etc. If there is sufficient charge in the battery, it is possible to drive solely on electric power. Whenthe accelerator pedal is pressed, only the electricmotor will be activated until the battery reaches acertain charge level. Above this level, the currentin the battery cannot supply the power requestedby the accelerator pedal and the combustionengine will start. When the hybrid battery's charge level is low, the combustion engine will start more frequently tosave the remaining current in the battery. Chargethe hybrid battery from a 120-240 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 con- sumption with an optimized mix between theelectric motor and gasoline engine, without com-promising on climate comfort or driving experi-ence. When faster acceleration is requested bythe driver, the electric driveline will be utilized tohelp provide maximum additional power. Thevehicle also monitors the driving conditions andautomatically engages all-wheel drive if neces-sary. All-wheel drive and extra electric power arealways available regardless of the battery'scharging status.
4 For vehicles with pneumatic suspension.