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

1
General
HDC can be compared to an automatic engine
brake. When you release the accelerator on
downhill gradients the car is normally braked
by means of the engine striving for low engine
idling speeds, so-called engine braking. 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 sensitivity of the
accelerator pedal decreases and becomes
more precise by means of the full actuation of
the pedal being restricted to adjusting engine
speed within a limited range. The brake system
brakes itself and provides the car with 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.
1 HDC is only available on the XC70.
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.
Function
HDC is engaged or disengaged using a switch
on the centre console. An indicator lamp in the
button illuminates when the function is
switched on. When HDC is operating the
symbol illuminates and the display
shows Hill descent control ON
03 Your driving environment

Hill Descent Control (HDC)

The function only operates in first gear position
and in reverse gear. For an automatic gearbox,
gear position 1 must be selected, which is
shown with the figure
display, see page 113.
NOTE
HDC cannot be activated in an automatic
gearbox with the gear selector in position
D.
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 foot-
brake.
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:
.
1 in the trip computer
03
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