The Stability Light comes on sometimes when fast lane change or uneven pavement
How does the system works?
May be sensor defect?

 

that is a question for google.
the short answer is the ebcm uses inputs from sensors: steering angle, yaw, pitch and roll and activates the abs system to correct a perceived understeer or oversteer conditions.

if there is a fault with the system, post the code that is set in the ebcm.