Vehicl
e Stabilit y Assis t (VSA ) Syste m
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.
Controllin g Tractio n Durin g
Straight-lin e Acceleratio n
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 andretard 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.
Controllin g Tractio n Durin g
Cornerin g
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.
Technica l Informatio n
DO
T Tir e Qualit y Gradin g (U.S . Cars )
Temperatur e
The temperature grades are A (the highest), B, and C, representing the
tire's resistance to the generation of
heat and its ability to dissipate heat when tested under controlledconditions on a specified indoor
laboratory test wheel. Sustained high
temperature can cause the material of the tire to degenerate and reduce
tire life, and excessive temperature can lead to sudden tire failure. The
grade C corresponds to a level of performance which all passenger car
tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent
higher levels of performance on the
laboratory test wheel than the
minimum required by law. Warning: The temperature grade for
this tire is established for a tire that
is properly inflated and not over-
loaded. Excessive speed, underinfla-
tion, or excessive loading eitherseparately or in combination, can
cause heat build-up and possible tire
failure.
Technica l Informatio n
