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 calipers 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 traction control event message over the HS-CAN. 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 the traction control event has ended. The PCM returns engine timing and fuel injectors to normal operation and the IPC extinguishes the stability-traction control indicator (sliding car icon). After the vehicle speed exceeds 100 km/h (62.1 mph), traction control is accomplished only through the PCM torque control.

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 indicator (sliding car icon).