Volvo XC90 Owner's Manual page 404

STARTING AND DRIVING
|| When shutting off
If the function is active and holding the
vehicle stationary using the normal
brakes (A symbol lit), the brake pedal
must be depressed while pressing the
button in order to deactivate Auto-hold.
• The function will remain off until it is reactiva-
ted.
• When Auto-hold is switched off, Hill Start
Assist (HSA) will remain active to help pre-
vent the vehicle from rolling backward when
starting up a hill.
Related information
• Auto-hold brakes (p. 401)
Hill Start Assist
4
402
Hill Start Assist
The function for assisting when starting the vehi-
4
cle on inclines (HSA ) helps prevent the vehicle
from rolling backward when starting on an uphill
gradient. When backing up a hill, HSA helps
prevent the vehicle from rolling forward.
The function retains pressure from the brake
pedal in the brake system for several seconds
after the brake pedal has been released.
This temporary braking effect is released after a
few seconds or when the driver begins driving.
Hill Start Assist is available even when the Auto-
hold brake function is switched off.
Related information
• Auto-hold brakes (p. 401)
• Brakes (p. 394)
Braking assist after a collision
In a collision in which the activation level is
reached for the pyrotechnic seat belt tensioners
or airbags, or if a collision with a large animal is
detected, the vehicle's brakes will be automati-
cally activated. This function is intended to help
prevent or reduce the effects of any subsequent
collision.
After a serious collision, it may no longer be pos-
sible to control and steer the vehicle. In order to
avoid or mitigate a possible further collision with
a vehicle or an object in the vehicle's path, the
brake assist system is activated automatically to
help stop the vehicle safely.
The brake lights and hazard warning flashers are
activated during braking. When the vehicle has
stopped, the hazard warning flashers will con-
tinue to flash and the parking brake will be
applied.
If braking is not appropriate, e.g. if there is a risk
of being hit by passing traffic, the driver can over-
ride the system by depressing the accelerator
pedal.
This function assumes that the brake system is
intact after a collision.
Brake assist is part of the Rear Collision Warning
and Blind Spot Information safety systems.