GMC 2012 Sierra - Manual (Page 331)

Black plate (55,1) GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-55
This feature is designed to 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 for a maximum of
two seconds to ensure that there
is no rolling. The brakes will
automatically release when the
accelerator pedal is applied within
the two‐second window. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, HSA may also apply
the trailer brakes. 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).
There may be situations on minor
hills (less than 5% grade) with a
loaded vehicle or while pulling a
trailer where HSA will not activate. Ride Control Systems
StabiliTrak ® System
The vehicle has a vehicle stability
enhancement system called
StabiliTrak. It is an advanced
computer-controlled system that
assists the driver with directional
control of the vehicle in difficult
driving conditions.
StabiliTrak activates when the
computer senses a discrepancy
between the intended path and the
direction the vehicle is actually
traveling. StabiliTrak selectively
applies braking pressure at any one
of the vehicle's brakes to assist the
driver with keeping the vehicle on
the intended path.
StabiliTrak is on automatically
whenever the vehicle is started. To
assist with directional control of the
vehicle, the system should always
be left on. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. See Trailer
Sway Control (TSC) on page 9‑105
for more information.
When the vehicle is started and
begins to move, the system
performs several diagnostic checks
to insure there are no problems.
The system may be heard or felt
while it is working. This is normal
and does not mean there is a
problem with the vehicle. The
system should initialize before the
vehicle reaches 32 km/h (20 mph).
In some cases, it may take
approximately 3.2 km (2 mi) of
driving before the system initializes.
If cruise control is being used
when StabiliTrak activates, the
cruise control automatically
disengages. The cruise control
can be re-engaged when road
conditions allow. See Cruise Control
on page 9‑58.
If the system fails to turn on or
activate, the StabiliTrak light along
with a message will be displayed on
the Driver Information Center (DIC).