Dynamic Driving Safety Systems
Fundamentals
Traction Control System
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Critical driving situations can occur not only during braking, but also while driving,
cornering, starting off, and accelerating (especially on wet or slippery roads). These
situations can make it difficult for the driver to react correctly, and can cause the vehicle
to become unstable.
•
The TCS helps to solve these problems by avoiding / reducing wheel spin. This is
achieved either by reducing the engine torque by sending a corresponding signal to the
PCM
(Powertrain Control Module) and / or by applying brakeforce to the spinning
wheel(s).
•
The TCS is incorporated to some ABS Hydraulic Unit/Control Module by minor changes
to the basic system, but is also integrated to all DSC systems installed on Mazda
vehicles.
•
Depending on the vehicle, different strategies may be used for the operation of the TCS.
The most common is that, when the control module recognizes that the wheel speed of
the driven wheels exceeds the wheel speed of the other wheels by a specified value, a
signal is sent to the PCM to reduce the engine torque. The PCM accordingly reduces the
engine torque output by closing the throttle valve (only on vehicles with electronic throttle
valve), adjusting the ignition timing, and / or by cutting fuel off. If the wheel spin still
exceeds the limit or if the speed of one wheel exceeds the wheel speed of the other
driven wheel by a specified value, brake force is applied by the hydraulic unit to the
corresponding wheel(s).
NOTE:
TCS does not completely avoid wheel spin, it operates only above a specified limit of
wheel spin.
Curriculum Training
01-15