Traction Control

When the drive wheels lose traction and begin to spin, the ABS module commands the hydraulic pump motor on and the HCU to open and close the appropriate solenoid valves to modulate the brake pressure to the brake caliper(s) while simultaneously sending a request to the PCM over the High Speed Controller Area Network (HS-CAN) to reduce engine torque to maintain vehicle traction. The PCM accomplishes this by minor incremental timing changes and fewer fuel injector pulses until the ABS module ends the request. The request ends when the driven wheel speed returns to the desired speed. After the vehicle speed exceeds 100 km/h (62 mph), the traction control is accomplished only through the PCM torque control.

The traction control system allows the driver to control use of the traction control system by enabling or disabling it. This is independent of the ABS, ESC and RSC® functions, which cannot be disabled by the driver. To disable or enable the traction control system, change the TRACTION CNTRL setting in the message center to ON or OFF. When the driver uses the message center and turns the traction control system off, the Instrument Panel Cluster (IPC) communicates traction control system status to the ABS module via the HS-CAN. The ABS module turns off the traction control system and commands the IPC to illuminate the stability/traction control indicator (sliding car icon) OFF, which indicates to the driver that the traction control system is disabled. The system automatically restores to full functionality when the ignition switch is cycled from OFF to RUN.