The ESC is the acronym for Electronic Stability control. The ESC is a braking system that combines the functions of a brake servo unit and the ABS(Antilock Braking System) equipment including ESP(Electronic Stability Program). The ESC is a technology that improves the safety of a vehicle's stability by detecting and reducing loss of traction. When ESC detects loss of a steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually. The Hill-start Assist Control(HAC) function helps the vehicle not to slip on a steep hill when starting up without depressing the brake pedal. When this function is operating, brake lamp turns on by the brake lamp relay for representing vehicle braking.