ESC: Electronic Stability Control
All 2012 model year vehicles come equipped with electronic stability control (ESC) standard, but electronic stability control has been an available option since 2008. These systems use many sensors to measure the dynamics of the vehicle and the intentions of the driver. The ESC system depends mainly on three main sensors that measure yaw, pitch, and steering angle.
Electronic Stability Control Computer System
Most 2008 and later vehicles have the ESC and ABS on a Class 3 Controller Area Network (CAN) bus system that operates at a high baud rate. The sensors for yaw, pitch, and steering angle are found on this network. Those sensors, and more, communicate with the stability control module in binary language via the CAN bus. The computer processor in the stability control takes in information, decides what’s happening, and decides what corrections should be made in real time with a very fast network and processor.
The ESC system measures the correction’s effectiveness of its correction with the brake system. The effectiveness is determined by the contact patch of the tires. The contact patch is influenced by the tire and chassis condition. The computer does not assign a value to the contact patch condition, and most systems have no parameters for it. The corrections and effectiveness are measured by the sensors in a high-speed feedback loop. The ESC will not set off a malfunction light if the contact patch condition crosses a threshold, but as it diminishes, more corrections will need to be made to bring the vehicle under control. As a shock or struts degrade, the pitch and yaw become harder to control. This change is usually very minute and is not noticed by the driver.