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

The ESC  and RSC®  functions are controlled by the ABS module and use the same wheel speed sensors and tone rings used for anti-lock braking. The ESC  and RSC®  functions also use input from the steering wheel rotation sensor, the stability control sensors (yaw rate, roll rate, longitudinal and lateral accelerometers) which are internal to the RCM  and information from other modules sent over the HS-CAN  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 rollover 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  that a stability event is taking place. When the IPC  receives this message, it flashes the stability/traction control indicator (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 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 sliding car icon.

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