Electronic Stability Control (ESC) and Roll Stability Control (RSC®) Systems

The ESC  and RSC®  systems are controlled by the ABS module and use the same wheel speed sensors and tone rings that are used for anti-lock braking. The ESC  and RSC®  systems also use input from the steering wheel rotation sensor, the stability control sensors (yaw rate, roll rate, longitudinal acceleration and lateral acceleration) which are internal to the Restraints Control Module (RCM) and information from other modules sent over the HS-CAN  bus to help maintain vehicle stability.

The ABS module uses the various sensors to continuously monitor vehicle roll motion and direction of travel relative to the driver's intended course. If the ABS module determines from all these inputs that the vehicle is unable to travel in the intended direction or that a condition exists for a potential roll-over event, it modulates brake pressure to the appropriate brake caliper(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  bus that a stability event is taking place. When the IPC receives this message, it will flash the sliding-car icon. During a stability event, conditions may require the involvement of the PCM to limit engine torque like it does for traction control. Once the stability condition has been corrected, the ABS module returns the solenoid valves in the HCU  to their normal position, deactivates the hydraulic pump motor and sends another message over the HS-CAN  bus indicating that the traction event has ended. The PCM returns engine timing and fuel injectors to normal operation and the Instrument Panel Cluster (IPC) extinguishes the sliding-car icon.

Certain DTCs being present in the ABS module may disable the ESC  and RSC®  systems. Depending on the DTCs present, the yellow ABS warning indicator and/or the sliding-car icon will be illuminated.