Chevrolet Impala Owner's Manual page 241

Hill Start Assist (HSA)
Some vehicles have a Hill Start
Assist (HSA) feature, which may be
useful when the vehicle is stopped
on a grade. This feature is designed
to temporarily prevent the vehicle
from rolling, either forward or
rearward, during vehicle drive off.
After the driver completely stops
and holds the vehicle in a complete
standstill on a grade, HSA will be
automatically activated. During the
transition period between when the
driver releases the brake pedal and
starts to accelerate to drive off on a
grade, HSA holds the braking
pressure to ensure that there is no
rolling. The brakes will automatically
release within a two-second window
of releasing the brake pedal, and
the vehicle may begin to roll. It will
not activate if the vehicle is in a
drive gear and facing downhill or if
the vehicle is facing uphill and in
R (Reverse).
HSA will activate on eAssist
vehicles while in gear and facing
down hill to assist in allowing a
smooth auto start.
Driving and Operating
Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak
electronic stability control system.
These systems help limit wheel slip
and assist the driver in maintaining
control, especially on slippery road
conditions.
TCS activates if it senses that any
of the drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak selectively applies
braking pressure to any one of the
9-33
®
, an