All-Wheel Drive - Volvo XC90 Owner's Manual

STARTING AND DRIVING

All-wheel drive*

All-wheel drive, AWD (All Wheel Drive), means
that the car is driving all four wheels at the same
time, which improves traction.
To achieve the best possible traction and prevent
wheel spin the motive force is distributed auto-
matically to the wheels with the best grip. All-
wheel drive also has a stabilising effect at higher
speeds. Under normal driving conditions, the
majority of power is transmitted to the front
wheels.
All-wheel drive characteristics vary depending on
the selected drive mode*.
Related information
•
Drive modes* (p. 362)
•
Low speed control* (p. 376)
368
Brake functions
The car's brakes are used to reduce the speed
or prevent the car from rolling.
Besides the foot brake and parking brake, the car
is equipped with several automatic brake assist
functions. These can assist the driver by not
needing to keep his/her foot on the brake pedal
when stationary at a traffic light, when starting on
an uphill gradient or when driving on a downhill
gradient.
Depending on the car's equipment, the following
auto braking functions are available:
•
Automatic braking when stationary
•
Hill start assist (Hill Start Assist)
•
Auto braking after a collision
•
Hill descent control (Hill Descent Control)*
Related information
•
Foot brake (p. 368)
•
Parking brake (p. 371)
•
Hill descent control* (p. 375)
•
Hill start assist (p. 374)
•
Automatic braking when stationary (p. 374)
•
Auto braking after a collision (p. 371)
Foot brake
The foot brake is used to reduce the car's speed
while driving.
Foot brake system
The car is equipped with two brake circuits. If a
brake circuit is damaged, the brake pedal will
engage deeper. Higher pressure on the pedal will
therefore be needed to produce the normal brak-
ing effect.
The driver's brake pedal pressure is assisted by a
brake servo.
WARNING
The brake servo only works when the engine
is running.
If the foot brake is used when the engine is
switched off then the pedal will feel stiff and a
higher pedal pressure must be used to brake the
car.
In very hilly terrain or when driving with a heavy
load the brakes can be relieved by using engine
braking in manual gearshift mode. Engine braking
is most efficiently used if the same gear is used
downhill as up. Use drive mode Off Road
increased engine braking while driving on steep
downhill gradients at low speeds.
* Option/accessory, for more information, see Introduction.
* for