Volvo XC90 TWIN ENGINE Owner's Manual page 444

STARTING AND DRIVING
Foot brake
The foot brake is part of the 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.
WARNING
In a de-energised car with the electric motor
and fuel-driven engine switched off it is not
possible 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 gearshift mode B.
Use drive mode Off Road for increased engine
braking while driving on steep downhill gradients
at low speeds.
Anti-lock braking system
The car has anti-lock brakes, Anti-lock Braking
System (ABS), which can prevent the wheels
from locking while braking and allows maintained
steering control. Vibration may be felt in the
brake pedal when this is engaged and this is nor-
mal.
A short test of the ABS system is made automat-
ically after the car has been started when the
driver releases the brake pedal. A further auto-
matic test of the system may be made at low
442
speed. The test may be felt as pulses in the
brake pedal.
Light braking charges the hybrid battery
The electric motor's engine brake is used during
light braking. The car's kinetic energy is then
converted to electrical energy instead, which is
used to charge the hybrid battery. Battery charg-
ing with electric motor braking is indicated in the
driver display.
The driver display indicates charging during electric
motor braking.
This function is active in the speed interval
150-5 km/h (93-3 mph). During heavier braking,
as well as outside the speed interval, braking is
supplemented by the hydraulic brake system. The
driver's display shows this by the indicator being
down in the red zone.
Symbols in the driver display
Symbol Specification
Check the brake fluid level. If the
level is low, fill with brake fluid and
check for the cause of the brake
fluid loss.
Fault in pedal sensor.
Constant glow for 2 seconds when
the engine is started: Automatic
function check.
Constant glow for more than 2
seconds: Fault in the ABS system.
The car's normal brake system is
still working, but without the ABS
function.
If the message Brake pedal Cha-
racteristics changed Service
required
is shown, the system for
"Brake-by-wire" is disengaged. The
brake pedal engages deeper and a
higher pedal pressure is required
to achieve braking effect.