VSA- Engine Drag Torque Control

Overview 

Downshifting on a slippery road may cause vehicle instability because engine braking may lock up the wheels. When engine braking begins to cause the wheels to lock up, the engine drag torque control commands the management ECU to increase the torque, helping to prevent tire slip.

Control 

The VSA modulator-control unit calculates the vehicle speed and acceleration of each wheel from each wheel speed sensor signal and makes a judgment on the slip condition of the wheel. The VSA modulator-control unit adjusts the drive torque based on the slip condition.