Volvo XC90 T8 TwinEngine Plug-In Hybrid, Owner'S Manual

Page: 340 / 534

STARTING AND DRIVING
* Option/accessory, for more information, see Introduction. 338
Starting and driving
The vehicle is equipped with an automatic trans-
mission that also makes it possible to shift gears
manually.
Certain functions can also be used when the
engine is not running, depending on the ignition
mode being used.
Related information
•
Starting the engine (p. 364)
•
Ignition modes (p. 362)
•
Automatic transmission (p. 387)
•
Opening/closing the fuel filler door (p. 355)
•
Parking brake (p. 344)
Brakes
The brake system is a hydraulic system consist-
ing of two separate brake circuits. If a problem
should occur in one of these circuits, it is still
possible to stop the vehicle with the other brake
circuit.
Brake system
If one of the brake circuits is not functioning,
more pressure will be needed on the brake pedal
(and the pedal will go down farther) for normal
braking effect.
If the brake pedal must be depressed farther
than normal and requires greater foot pressure,
the stopping distance will be longer.
Pressure on the brake pedal is enhanced by the
power braking function.
WARNING
If vehicle does not have electrical current and
both the electric motor and gasoline engine
are switched off, the brakes cannot be used
to stop the vehicle.
When the Hill Start Assist function is being used,
it will take slightly longer for the brake pedal to
return to its normal position if the vehicle is
parked on an incline or uneven surface.
When driving in very hilly areas or if the vehicle is
carrying a heavy load, using brake mode B to
augment the brakes or the
Off Road *
drive
mode can also be used to increase the engine
braking effect at low speeds.
Anti-lock Braking System ABS
The ABS system helps to improve vehicle control
(stopping and steering) during severe braking
conditions by limiting brake lockup.
When ABS is operating, there may be some
vibration in the brake pedal, which is normal.
The system performs a brief self-diagnostic test
when the engine has been started and driver
releases the brake pedal. Another automatic test
may be performed when the vehicle first reaches
a speed of approximately 6 mph (10 km/h). The
brake pedal will pulsate several times and a
sound may be audible from the ABS control
module, which is normal.
Function check when the engine is
started
A Plug-in Hybrid is equipped with a "brake by
wire" brake system. A function check is per-
formed each time the engine is started and the
driver depresses the brake pedal to move the
gear selector from
P
.
In certain cases, a message may appear in the
instrument panel saying that pressure on the
brake pedal is too low. Press harder on the pedal.
Light braking charges the hybrid battery
When the brakes are applied lightly, the electric
motor's braking function is used, which converts