Roll Stability Control (RSC)

WARNING: This page is about a different car, the 2017 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The ABS module continuously monitors the vehicle motion relative to the intended course. This is done by using sensors to compare the steering wheel sensor messages, yaw rate sensor messages, lateral acceleration sensor messages, longitudinal acceleration sensor messages and roll rate sensor messages with the actual vehicle motion. The ABS module determines steering wheel angle using information from the wheel speed sensors, the PSCM and the RCM. Steering angle information is calculated by the PSCM and sent to the ABS module over the HS-CAN2. Vehicle yaw rate, lateral acceleration, longitudinal acceleration and roll rate information is sent to the ABS module from the RCM over the HS-CAN2. If the ABS module determines from the inputs the vehicle is becoming unstable, the brake pressure to the appropriate brake caliper(s) is modulated 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 calculates how much engine torque reduction is required to help stabilize the vehicle and sends this torque reduction message, along with an RSC event message, to the GWM over the HS-CAN2. The GWM sends the torque reduction message to the PCM over the HS-CAN1 and the RSC event message to the IPC over the HS-CAN3. When the PCM receives the torque reduction message, it adjusts engine timing and decreases fuel injector pulses to reduce the engine torque to the requested level. When the IPC receives this message, it flashes the stability-traction control indicator (sliding car icon).

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 stops sending the RSC event and torque reduction messages. The PCM returns engine timing and fuel injectors to normal operation and the IPC extinguishes the stability-traction control indicator (sliding car icon).

RSC does not operate with the transmission in REVERSE. RSC is disabled if there is a wheel speed sensor, stability sensor or steering angle sensor DTC present in the ABS module. RSC is also disabled if there is a communication error between the ABS module and the PSCM or the module and the RCM. When RSC is disabled, the ABS module sends a message to the GWM along the HS-CAN2 which gateways the message to the IPC over the along the HS-CAN3 to illuminate the stability-traction control OFF indicator (sliding car OFF icon).