Hill Descent Control (Hdc) - Volvo XC70 Owner's Manual

1
General
HDC can be compared to an automatic
engine brake. When you release the accelera-
tor on downhill gradients the car is normally
braked by means of the engine striving for low
engine idling speeds, so-called engine brak-
ing. But the steeper the road and the more
load there is in the car, the faster the car rolls
despite engine braking. In order to then
reduce speed the driver has to assist using
the footbrake.
The function makes it possible to increase/
reduce speed on steep downhill gradients,
with a foot only on the accelerator pedal,
without using the footbrake. The brake sys-
tem brakes itself and automatically provides a
low and even speed, so allowing the driver to
fully focus on steering.
HDC is particularly helpful on steep gradients
with an uneven road surface and slippery sec-
tions. E.g. when launching a boat on a trailer
from a ramp.
WARNING
HDC does not work in all situations, but is
instead only intended to be supplementary
assistance.
The driver always has ultimate responsibility
that the car is driven safely.
1
HDC is only available on the XC70 and is
standard.
Function
HDC is engaged or disengaged using a
switch on the centre console. A lamp in the
button illuminates when the function is
engaged. When HDC is operating the
symbol illuminates and the display shows
Descent Control ON .
The function only operates in first gear posi-
tion and in reverse gear. For an automatic
gearbox, gear position 1 must be selected,
which is shown with the figure 1
computer display, see page 93.
NOTE
HDC cannot be activated in an automatic
gearbox with the gear selector in position D .
03 Your driving environment

Hill Descent Control (HDC)

Operation
HDC allows the car to roll at a maximum of
10 km/h forwards with engine braking and
7 km/h backwards. However, any speed
within the gear's speed register can be
selected using the accelerator pedal. When
the accelerator pedal is released, the car is
braked quickly to 10 or 7 km/h respectively,
irrespective of the hill's gradient and without
the need for the footbrake.
The brake lights come on automatically when
the function is operating. The driver can brake
or stop the car at any time by using the foot-
brake.
HDC is deactivated:
• with the on/off button on the centre con-
sole
Hill
• if a gear higher than 1 is selected on a
manual gearbox
• if a gear higher than 1 is selected on an
automatic gearbox, or if the gear selector
is moved to position D .
The function can be disengaged at any time.
in the trip
If it takes place on a steep downhill gradient
then the braking effect will not release
directly, but slowly instead.
NOTE
When HDC is activated, engine response dur-
ing acceleration seems slower than normal.
03
97