Roll Stability Control™

The ABS  module continuously monitors the vehicle motion relative to the intended course. This is done by using sensors to compare the wheel speed sensor input, throttle position input, steering wheel input and the roll rate sensor input with that of the actual vehicle motion. On vehicles without active park assist, steering wheel angle information is calculated by the PSCM  and is sent to the ABS  module over the HS-CAN  . On vehicles with active park assist, steering wheel angle information is sent to the SCCM  from the steering wheel angle sensor, this information is sent to the ABS  module over the HS-CAN  . On vehicles with active park assist, the ABS  module also receives steering angle information from the PSCM  . The ABS  module compares the steering angle information received from both modules against one another. Regardless of active park assist capabilities, vehicle roll rate information is sent to the ABS  module from the RCM  over a private HS-CAN  . The PCM  sends the throttle position sensor information to the ABS  module over the HS-CAN  . The wheel speed sensor information comes directly from the ABS  wheel speed sensors.

If the ABS  module determines from the inputs that the vehicle is becoming unstable, the ABS  module 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 vehicle stability event is taking place. When the PCM receives this message, it assists with vehicle stability control by adjusting engine timing and decreasing fuel injector pulses. When the IPC  receives this message, it flashes the stability/traction control indicator (sliding car icon). By adjusting brake and engine torque the system can reduce the cornering forces and, therefore, the total roll movement acting on the vehicle. Once the vehicle instability 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 event has ended. The PCM returns engine timing and fuel injectors to normal operation and the IPC  extinguishes the sliding car icon.

The RSC®  function does not operate with the transmission in REVERSE. The ABS  module disables the RSC®  function if there are any wheel speed sensor, stability sensor or steering angle sensor DTCs  present in the ABS  module. Also, if there is a communication error between the ABS  module and the PSCM  , SCCM  , PCM  or the RCM  , the RSC®  function is disabled. When the RSC®  function is disabled, the ABS  module sends a message over the HS-CAN  to the IPC  to illuminate both the sliding car icon and the stability/traction control disabled indicator (sliding car OFF icon).