2018 VOLVO XC90 T8 brakes

HYBRID INFORMATION
406
General information about TwinEngine
Twin Engine vehicles are driven just like any other vehicle, but certain functions differ from avehicle powered exclusively by gasoline. Theelectric motor powers the vehicle primarily at lowspeeds; the gasoline engine is used at higherspeeds or during more active driving.
The instrument panel displays Twin Engine-spe- cific information - charging information, selecteddrive mode, distance to discharged battery andhybrid battery charge level. Different drive modes can be selected while driv- ing, e.g. electric power only or, if more power isneeded, a combination of electric and gasolinepower. The vehicle calculates the optimal combi-nation of driveability, driving experience, environ-mental impact and fuel economy for the selecteddrive mode. In order to function optimally, the hybrid battery (and its electrical drive systems) and the gasolineengine (and its drive systems) must be at thecorrect operating temperature. Battery capacitycan be considerably reduced if the battery is toocold or too hot. Preconditioning prepares thevehicle's drive systems and passenger compart-ment before driving to help reduce both wear andenergy consumption. It also helps increase thehybrid battery's range. The hybrid battery, which powers the electric motor, is recharged using the charging cable. Itcan also be recharged during light braking and through engine braking in gear position
B. The
combustion engine can also help recharge thehybrid battery.
Important
No electrical current
Keep in mind that if there is no electrical current to the vehicle, i.e. the ignition is switched off orthe start battery is discharged, certain functionssuch as brakes, power steering, etc. will not work.
WARNING
If the vehicle does not have electrical current and both the electric motor and the gasolineengine are switched off, the brakes cannot beused to stop the vehicle.
Towing not permitted
Never tow a Twin Engine vehicle behind another vehicle, as this could damage the electric motor.
Exterior engine noise
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 especially true at low speeds, e.g. inparking lots.
High-voltage electrical current
WARNING
Several components in the vehicle work with high voltage that can be hazardous in case ofan incorrect procedure. These componentsand any orange wiring in the vehicle may onlybe handled by trained and qualified Volvoservice technicians.
Do not touch anything that is not clearly descri- bed in this Owner's Manual.
Related information
• Charging the hybrid battery (p. 407)
• Hybrid gauge (p. 87)
• Drive modes (p. 445)
• Starting and stopping preconditioning(p. 231)
• Hybrid battery (p. 619)
• Factors affecting electric motor range(p. 458)
• Gear selector positions for automatic trans-missions (p. 439)
• Towing using a towline (p. 476)

HYBRID INFORMATION
}}
407
Charging the hybrid battery In addition to the conventional fuel tank, your vehicle is also equipped with a rechargeablelithium-ion hybrid battery.
The hybrid battery can be recharged using the charging cable stored in a storage space in thecargo compartment.
WARNING
The hybrid electrical system in your vehicle uses high voltage electrical current. Any dam-age to this system or to the hybrid batterymay result in the danger of overheating, fire,or serious injury. If the vehicle is involved in acollision or subjected to flooding, fire, etc.,have it inspected by a trained and qualifiedVolvo service technician. Prior to this inspec-tion, the vehicle should be parked outdoors ata safe distance from any building or poten-tially flammable materials.
The hybrid battery's charging time depends on the charging current used.
NOTE
The capacity of the hybrid battery diminishes somewhat with age and use, which couldresult in increased use of the gasoline engineand consequently, slightly higher fuel con-sumption.
WARNING
If the hybrid battery needs to be replaced, this may only be done by Volvo retailer or author-ized Volvo workshop.
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 hybrid battery's charging process alsocharges the vehicle's start battery. 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 or not available at all. The electric motor cannot be used if the battery'stemperature is too low or too high. If the PUREdrive mode is selected, the gasoline engine willstart.
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 downgrades.
The vehicle can also generate current to the hybrid battery to charge it.
• The hybrid battery can also be recharged bylightly depressing the brake pedal, i.e. duringlight braking. This converts the vehicle'skinetic energy to electrical energy, which isused to charge the hybrid battery.
• In gear position
B, the electric motor brakes
the vehicle when the accelerator pedal is

STARTING AND DRIVING
}}
429
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 a num-ber of automatic brake assist functions. Thesesystems help the driver by e.g. keeping the vehi-cle stationary when the brake pedal is notdepressed (e.g. at a traffic light or intersection),when starting up a hill or when driving down a hill. Depending on how the vehicle is equipped, the following brake assist functions may be included:
• Auto-hold brakes (Auto Hold)
• Hill Start Assist (Hill Start Assist)
• Braking assist after a collision
• City Safety
• Hill Descent Control (Hill Descent Control)
Related information
•
Brakes (p. 429)
• Parking brake (p. 432)
• Auto-hold brakes (p. 436)
• Braking assist after a collision (p. 437)
• Hill Start Assist (p. 437)
• City Safety
™ (p. 335)
• Hill Descent Control (p. 454)
Brakes The brake pedal is used to apply the vehicle's regular brakes, which are part of the brake sys-tem.
The vehicle is equipped with two brake circuits. If one brake circuit is damaged, the brake pedal willgo down further when depressed. More pressurewill then be required from the driver for normalbraking effect.
WARNING
If the vehicle does not have electrical current and both the electric motor and the gasolineengine are switched off, the brakes cannot beused to stop 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. Use the Off Road drive mode to increase the engine braking effect when driving on steepdowngrades at low speeds.
Anti-lock brakesThe vehicle is equipped with an Anti-lock BrakingSystem (ABS), which can help prevent thewheels from locking and help maintain steeringcontrol when braking. Vibrations may be felt fromthe brake pedal when ABS is operating, which isnormal. After the vehicle is started, a brief test of the ABS system is automatically performed when the driver releases the brake pedal. An additionalautomatic test of the system may be performedwhen the vehicle is traveling at a low speed. Dur-ing the test, the brake pedal may feel as though itis pulsating.
Light braking charges the hybrid batteryWhen the brakes are applied lightly, the electricmotor braking function is used. This converts thevehicle's kinetic energy into electrical energy,which is used to charge the hybrid battery. Whenthe battery is being charged with the electricmotor braking function, this will be indicated inthe instrument panel.
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 used to

||
STARTING AND DRIVING
430augment braking. This is indicated in the instru- ment panel with the pointer down in the red area.
Symbols in the instrument panel
SymbolMeaning
A
B
Check the brake fluid level. If the level is low, fill brake fluid andcheck to determine the reason forthe loss of brake fluid.
A
BFault in pedal sensor.
SymbolMeaning
A
BSteady glow for 2 seconds after the engine is started: Automaticfunction check. Steady glow for more than 2 sec- onds: Fault in the ABS system. Thevehicle's regular brake system isstill working, but without the ABSfunction.
If the message Brake pedal Cha-
racteristics changed Service required
is displayed, the "Brake-
by-wire" system is not functioning properly. The brake pedal will godown further than normal andgreater pressure will be needed onthe pedal to achieve braking effect.
A Canadian models.
B US models.
WARNING
• If both symbols illuminate at the same time and the brake level is below the
MIN
mark in the reservoir or if a brake system- related message is shown in the instru-ment panel: DO NOT DRIVE. Have thevehicle towed to a trained and qualifiedVolvo service technician and have thebrake system inspected.
• If both symbols illuminate at the sametime and the brake level is normal (notbelow the MIN mark in the reservoir) or ifa brake system-related message isshown in the instrument panel: drive thevehicle carefully to an authorized Volvoworkshop and have the brake systeminspected by a trained and qualified Volvoservice technician.
Related information
• Brake Assist System (p. 431)
• Auto-hold brakes (p. 436)
• Hill Start Assist (p. 437)
• Braking on wet roads (p. 431)
• Braking on salted roads (p. 431)
• Maintenance of the brake system (p. 432)
• Brake lights (p. 160)

STARTING AND DRIVING
431
Brake Assist System
The brake enhancing system, Brake Assist
System (BAS), helps increase braking force andthereby reduce braking distance.
The system monitors the driver's braking habits and increases braking force when necessary.Braking force can be increased up to the point atwhich the ABS intervenes. The function is deacti-vated when pressure on the brake pedal isdecreased.
Related information
• Brakes (p. 429)
Braking on wet roads
Prolonged driving in heavy rain without braking may cause braking effect to be slightly delayedthe first time the brakes are applied.
This may also occur after washing the vehicle. It will then be necessary to apply greater pressureto the brake pedal. You should therefore maintaina greater distance to the vehicle ahead. Firmly apply the brakes after washing the vehicle or driving on wet roads. This helps warm up thebrake discs, enabling them to dry more quicklyand protecting them against corrosion. Considerthe current traffic situation when braking.
Related information
• Brakes (p. 429)
• Braking on salted roads (p. 431)
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. Maintain an extra large safety distance to the vehicleahead. 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 have fin-ished driving and before driving again.
Related information
•Brakes (p. 429)
• Braking on wet roads (p. 431)

STARTING AND DRIVING
432
Maintenance of the brake system
Regularly check the brake system components for wear.
To keep the vehicle as safe and reliable as possi- ble, follow the Volvo service schedule specified inthe Warranty and Maintenance Records Informa-tion booklet. New and replaced brake pads andbrake discs do not provide optimal braking effectuntil they are "broken in" by driving a few hun-dred kilometers (miles). Compensate for thereduced braking effect by applying greater pres-sure to the brake pedal. Volvo recommends onlyusing brake pads approved 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 the inspection- an authorized Volvo workshop is recom-mended.
Related information
• Brakes (p. 429)
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 the brake's elec-tric motor. This sound can also be heard duringthe automatic function check of the parkingbrake. If the vehicle is stationary when the parking brake is applied, it will only be applied to the rearwheels. If it is applied while the vehicle is moving,the normal brakes will be used on all four wheels.Braking will be transferred to only the rearwheels when the vehicle is almost stopped.
Related information
•Activating and deactivating the parking brake(p. 433)
• Parking on a hill (p. 434)
• Parking brake malfunction (p. 435)
• Auto-hold brakes (p. 436)

STARTING AND DRIVING
436
Auto-hold brakesWith the Auto-hold brake function, the driver can release the brake pedal and the brakes willremain applied, for example, when the vehiclehas stopped at a traffic light or intersection.
When the vehicle stops, the brakes are activated automatically. The function can use either thenormal brakes or the parking brakes to keep thevehicle stationary and works on flat surfaces orhills. When driving off, the brakes will be automat-ically released if the driver's seat belt is buckled.
NOTE
When braking to a stop on an uphill or down- hill gradient, depress the brake pedal withslightly more force than usual before releas-ing to ensure that the vehicle cannot move atall.
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
SymbolMeaning
This symbol illuminates when the function is using the normal brakesto keep the vehicle stationary.
A
B This symbol illuminates when the function is using the parking braketo keep the vehicle stationary.
A
Canadian models.
B US models.
Related information
• Activating and deactivating Auto-hold at a standstill (p. 436)
• Brakes (p. 429)
• Parking brake (p. 432)
• Hill Start Assist (p. 437)
Activating and deactivating Auto-hold at a standstill The Auto-hold brake function at a standstill is activated with the button in the tunnel console.
–Press the button in the tunnel console to activate or deactivate the function.
> The indicator light in the button will illumi-
nate when the function is activated. The function will remain active the next timethe vehicle is started.

STARTING AND DRIVING
}}
437
When shutting offIf the function is active and holding the vehicle stationary using the normalbrakes (A symbol lit), the brake pedalmust be depressed while pressing the
button in order to deactivate Auto-hold.
• The function will remain off until it is reactiva- ted.
• When Auto-hold is switched off, Hill StartAssist (HSA) will remain active to help pre-vent the vehicle from rolling backward whenstarting up a hill.
Related information
•Auto-hold brakes (p. 436)
Hill Start Assist
The function for assisting when starting the vehi- cle on inclines, Hill Start Assist (HSA), helpsprevent the vehicle from rolling backward whenstarting on an uphill gradient. When backing upa 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 driving. Hill Start Assist is available even if the Auto-hold brake function is switched off.
Related information
• Auto-hold brakes (p. 436)
• Brakes (p. 429)
Braking assist after a collision In a collision in which the activation level is reached for the pyrotechnic seat belt tensionersor airbags, or if a collision with a large animal isdetected, the vehicle's brakes will be automati-cally activated. This function is intended to helpprevent or reduce the effects of any subsequentcollision.
After a serious collision, it may no longer be pos- sible to control and steer the vehicle. In order toavoid or mitigate a possible further collision witha vehicle or an object in the vehicle's path, thebrake assist system is activated automatically tohelp stop the vehicle safely. The brake lights and hazard warning flashers are activated during braking. When the vehicle has stopped, the hazard warning flashers will con-tinue to flash and the parking brake will beapplied. If braking is not appropriate, e.g. if there is a risk of being hit by passing traffic, the driver can over-ride the system by depressing the acceleratorpedal. This function assumes that the brake system is intact after a collision. Brake assist is part of the Rear Collision Warning and Blind Spot Information safety systems.