Six Star Magazine Six Star Magazine Winter 2008/2009 | Page 36

TECH TALK

SLIPS,

SLIDES &

SAFETY
WHAT IS VDC?
The Vehicle Dynamics Control (VDC)
system (otherwise know as Electronic
Stability Control) receives information
about the car from various sensors.
These sensors monitor steering angle
(the amount the steering wheel is
turned), yaw (how much the nose of the
car moves from side to side), individual
wheel speed and lateral G load (the
amount of force being generated
during cornering).
These sensors feed your car’s
onboard computer with information
constantly, measuring how the car is
reacting to your touch on the steering
wheel, brake pedal and accelerator pedal
at all times.
The VDC system then uses this
information to decide whether corrective
action is needed to keep the car stable
and in control; this action takes various
forms, including reducing engine output,
applying the brakes to an individual
wheel or locking the AWD system.
VDC IN ACTION
Now that we know all these facts
about the complex inner workings of
your Subaru’s VDC system, how the
system works in real-life situations
becomes very simple to explain.

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Imagine you are driving down the
highway and you hit a patch of ice – your
car starts going sideways to the right.
The onboard computer knows that
the car is sliding based on information
from the yaw and lateral G sensors. The
steering angle sensor and wheel speed
sensors tell the computer that you are
not going in the direction you want to
go. So... what happens?
The VDC system automatically
applies the left rear brake to pull the
car back in line and momentarily locks
the car’s front and