Trailer Sway Control

Trailer sway control is a unique function of the vehicle dynamic system that uses steering wheel angle information from the Steering Column Control Module (SCCM) (vehicles with active park assist) or from the Power Steering Control Module (PSCM) (vehicles without active park assist) and the yaw information from the Restraints Control Module (RCM) to determine if a trailer sway event is taking place. Trailer sway is the undesirable yaw force a trailer can apply to the towing vehicle. If it is determined that an event is taking place, 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. At the same time, the Anti-Lock Brake System (ABS) module sends a message over the High Speed Controller Area Network (HS-CAN) that a trailer sway event is taking place. When the Powertrain Control Module (PCM) receives this message, it assists with trailer sway 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) and displays TRAILER SWAY, REDUCE SPEED in the message center. Once the trailer sway 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.

Trailer sway control only activates when vehicle speed is greater than 65 kmh (40.4 mph). Any malfunction that disables the Roll Stability Control (RSC) function of the vehicle dynamic system also disables trailer sway control. Trailer sway control can also be disabled by the driver through the menu in the message center. Regardless of the chosen state (enabled or disabled) set by the driver, trailer sway control is enabled at each ignition key cycle.