Electronic Stability Control


Electronic Stability Control (ESC) systems work by using a network of sensors to continuously measure and compare a driver's intended direction of travel (measured by the SAS) to a vehicle's actual direction of travel (measured by sensors calculating lateral acceleration, vehicle rotation [yaw] and individual wheel speeds).

If the intended direction differs enough from the vehicle's actual direction to indicate loss of steering control, ESC automatically engages to operate some or all of a variety of vehicle functions including the brakes, throttle, traction controls and steering to help the driver maintain control of the vehicle.

Numerous studies confirmed the effectiveness of ESC in helping the driver maintain control, thereby saving lives and reducing the severity of crashes.

In 2004, the National Highway and Traffic Safety Administration (NHTSA) confirmed the results of earlier studies and concluded that ESC could reduce crashes by 35%.

By 2006, NHTSA issued a requirement that all new vehicles weighing up to 10,000 pounds be equipped with ESC by 2012.

Though commonly known as Electronic Stability Control, OEMs refer to the system by different names such as Active Stability Control (ASC), Dynamic Stability Control (DSC), Precision Control System (PCS), Vehicle Dynamic Control (VDC), Vehicle Stability Assist (VSA), and others.

ESC systems may utilitze the following:

• Steering angle sensor
• Lateral acceleration sensor
• Yaw rate sensor
• Torque angle sensors
• Wheel speed sensors
• Throttle pedal position sensor
• Anti-Lock Brake system (ABS)


The primary function of ESC is to avoid the crashes and rollovers caused by oversteering or understeering a vehicle.

"Understeer" (also known as "push") is a term describing a condition where the vehicle does not turn as quickly as the angle of the front wheels are demanding. The car does not respond to the steering input and continues a straight path.

“Oversteer” is a term describing a condition where the vehicle wants to turn too far, with the back end sliding around. This typically results in the vehicle spinning around.

ESC relies on accurate steering input from SAS to analyze either situation and apply appropriate measures to help direct the vehicle on the intended path.


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