I found the following info regarding the VSC indicator
Vehicle Skid Control (VSC) senses the onset of loss of lateral traction and helps the driver stay on track. Input from four wheel-speed sensors, a yaw-rate (directional) sensor, a deceleration sensor, and a steering-wheel-angle sensor is communicated to the VSC computer. The system has the ability to reduce power and to control the brake actuator. Working with both ABS and TRAC, the VSC system helps the driver to compensate for loss of lateral traction, which can cause skids and loss of vehicle control. Lexus Vehicle Skid Control (VSC) is an electronic system designed to help the driver maintain vehicle control under adverse conditions. It is not a substitute for safe driving practices. Factors including speed, road conditions and driver steering input can all affect whether VSC will be effective in preventing a loss of control.