Electronic Stability Control (ESC) System

The ESC  system is controlled by the ABS module and uses the same wheel speed sensors and wheel bearing magnetic strips used for anti-lock braking. The ESC  system also uses input from the stability control sensors for the ESC  system to help maintain vehicle stability. They include the yaw rate sensor, lateral accelerometer and longitudinal accelerometer and are located in the Restraints Control Module (RCM).

The ABS module uses the various sensors to continuously monitor vehicle direction of travel relative to the intended course. If the ABS module determines from all these inputs that the vehicle is unable to travel in the intended direction, it modulates brake pressure to the appropriate brake caliper(s) or wheel cylinder(s) by opening and closing the appropriate solenoid valves inside the HCU  while the hydraulic pump motor is activated. At the same time, the ABS module sends a message over the HS-CAN  that a stability event is taking place. When the IPC  receives this message, it flashes the sliding-car icon. Under certain conditions during a stability event, the PCM may be requested to reduce engine torque as it does for traction control. Once the stability condition has been corrected, the ABS module sends another message over the HS-CAN  indicating that the event has ended. The PCM returns engine timing and fuel injectors to normal operation and the IPC  turns off the stability/traction control indicator (sliding-car icon).

Certain DTCs being present in the ABS module may disable the ESC  system. Depending on the DTCs present, the yellow ABS warning indicator and/or the stability/traction control indicator (sliding-car icon) light is illuminated.