Acura 2000 RL - Owner's Manual - Manual (Page 303)

Vehicle Stability Assist (VSA) System
The Vehicle Stability Assist system
(VSA) monitors the car's actions
during straight-line acceleration and
cornering behavior. It reduces
engine power and applies selective
braking if it senses any loss of
traction.
Controlling Traction During
Straight-line Acceleration
If one drive wheel is turning faster
than the other, or both drive wheels
are turning faster than the non-
driven wheels, VSA senses
wheelspin. It reduces engine power
and applies braking at the wheels as
necessary to increase traction.
To do this, VSA monitors the pulse
frequencies from the wheel speed
sensors. It also uses information
from the steering wheel angle sensor
and the lateral acceleration sensor to
determine if the car is accelerating in
a straight line or if it is cornering.
VSA can then calculate how much
wheelspin, if any, to allow. It signals
the ECU to reduce fuel flow and
retard ignition timing. This reduces
available engine power. The ECU
will also apply braking at the wheels
as necessary. When wheelspin has
been controlled, braking and engine
control return to normal.
Controlling Traction During
Cornering
VSA monitors steering input and the
car's expected response to that input.
VSA's yaw rate sensor measures the
car's actual cornering behavior.
If VSA determines that the car is
turning more or less than expected,
the system reduces engine power
and applies braking at the
appropriate wheel to try and
maintain adequate traction during
cornering.
VSA uses the same wheel speed
sensor assemblies as the ABS.
Additional sensors measure steering
wheel angle, lateral acceleration, and
yaw rate.
The control unit monitors the VSA
circuitry while driving. If it senses a
problem, it turns off the system and
illuminates the VSA System
Indicator on the instrument panel.
Technical Information
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