Traction Control Function

The ABS module continuously monitors and compares the rotational speed of the drive wheels in relation to the non-driven wheels. When the drive wheels begin to spin faster than the non-driven wheels, 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 traction event is taking place. When the PCM receives this message, it assists with traction 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). Once the driven wheel speed returns to the desired speed, 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. After the vehicle speed exceeds 100 kmh (62.1 mph), traction control is accomplished only through the PCM torque control.

The traction control system can be disabled by the driver through the menu in the message center by changing the TRACTION CNTRL setting in the message center from ON to OFF. This is independent of the ABS, ESC and RSC functions, which cannot be disabled by the driver. When the driver disables the traction control function through the message center, the IPC communicates traction control system status to the ABS module via the HS-CAN  . The ABS module takes no further action in regards to traction control until the driver activates the function or until the ignition is cycled from OFF to ON.

The ABS module disables the traction control function if there are any wheel speed sensor or solenoid valve DTCs  present in the ABS module. The traction control function is also disabled if there is a communication error between the ABS module and the PCM. When the traction control function is disabled, the ABS module sends a message to the IPC to illuminate the stability/traction control disabled indicator (sliding car OFF icon).