Curve Control

The Anti-Lock Brake System (ABS) module continuously monitors the vehicle motion relative to the intended course. This is done by using sensors to compare the steering wheel input, the yaw rate sensor input, the lateral acceleration sensor input and the longitudinal acceleration sensor input with that of the actual vehicle motion. The Steering Column Control Module (SCCM) (vehicles with active park assist) or Power Steering Control Module (PSCM) (vehicles without active park assist) sends the steering wheel angle and rate of change information to the Anti-Lock Brake System (ABS) module over the High Speed Controller Area Network (HS-CAN) while the Restraints Control Module (RCM) sends the yaw rate, lateral acceleration and longitudinal acceleration sensor information to the Anti-Lock Brake System (ABS) module over a private High Speed Controller Area Network (HS-CAN). If the Anti-Lock Brake System (ABS) module determines from the inputs that the vehicle is experiencing over-steer or under-steer, the module sends a message over the High Speed Controller Area Network (HS-CAN) that a curve control event is taking place. When the Powertrain Control Module (PCM) receives this message, it assists with curve control by adjusting engine timing and decreasing fuel injector pulses. When the Instrument Panel Cluster (IPC) receives this message, it flashes the stability/traction control indicator (sliding car icon). The Anti-Lock Brake System (ABS) module continues to monitor the sensor inputs while the Powertrain Control Module (PCM) assists with curve control. If the Anti-Lock Brake System (ABS) module determines that Powertrain Control Module (PCM) intervention is insufficient to control the stability event, the Anti-Lock Brake System (ABS) module modulates brake pressure to the appropriate brake caliper(s) by opening and closing the appropriate solenoid valves inside the Hydraulic Control Unit (HCU) while the hydraulic pump motor is activated. Once the vehicle instability has been corrected, the Anti-Lock Brake System (ABS) module returns the solenoid valves in the Hydraulic Control Unit (HCU) to their normal position, deactivates the hydraulic pump motor and sends another message over the High Speed Controller Area Network (HS-CAN) bus indicating that the event has ended. The Powertrain Control Module (PCM) returns engine timing and fuel injectors to normal operation and the Instrument Panel Cluster (IPC) extinguishes the sliding car icon.

The Curve Control function does not operate with the transmission in REVERSE. The Anti-Lock Brake System (ABS) module disables the Curve Control function if there are any wheel speed sensor, stability sensor or steering angle sensor Diagnostic Trouble Codes (DTCs) present in the Anti-Lock Brake System (ABS) module. Also, if there is a communication error between the Anti-Lock Brake System (ABS) module and the Power Steering Control Module (PSCM), the Steering Column Control Module (SCCM) or the Restraints Control Module (RCM) the Curve Control function is disabled. When the Curve Control function is disabled, the Anti-Lock Brake System (ABS) module sends a message over the High Speed Controller Area Network (HS-CAN) to the Instrument Panel Cluster (IPC) to illuminate both the sliding car icon and the stability/traction control disabled indicator (sliding car OFF icon).