Traction Control System

The traction control system is controlled by the ABS module and uses the same wheel speed sensors and tone rings that are used for the ABS. The ABS module continuously monitors and compares the rotational speed of each wheel and when it detects a wheel spinning excessively, modulates brake pressure to the appropriate brake caliper. This is accomplished 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 control 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 IC receives this message, it flashes the stability/traction control indicator (sliding-car icon). Once the affected wheel returns to normal 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 indicating that the traction event has ended. The PCM returns engine timing and fuel injectors to normal operation and the IC extinguishes the stability/traction control indicator.

Once vehicle speed reaches or exceeds 100 km/h (62 mph), traction control is accomplished only through the PCM.

If the anti-lock control system is disabled due to DTCs being present in the ABS module, the traction control system is disabled. When the traction control system is disabled due to DTCs being present, both the ABS warning indicator and the stability/traction control indicator are illuminated.