Traction Control

WARNING: This page is about a different car, the 2014 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

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 calculates how much engine torque reduction is required to eliminate the wheel slip and sends this torque reduction message to the PCM over the HS-CAN. The ABS module also sends a traction event message to the BCM over the HS-CAN , the BCM then relays this message to the IPC over the MS-CAN . When the PCM receives the torque reduction message, it adjusts engine timing and decreases fuel injector pulses to reduce the engine torque to the requested level. When the IPC receives the traction event 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 stops sending the traction event and torque reduction messages. The PCM returns engine timing and fuel injectors to normal operation and the IPC extinguishes the stability-traction control indicator (sliding car icon). Once vehicle speed exceeds 100 km/h (62 mph), traction control is accomplished only through the PCM torque control.

On vehicles equipped with a message center and steering wheel switches, the traction control system can be disabled by the driver through the message center by changing the TRACTION CNTRL setting in the message center from ON to OFF. This is independent of ABS , Electronic Stability Control (ESC) and Roll Stability Control (RSC), all of which cannot be disabled by the driver. When the driver disables the traction control function through the message center, the IPC illuminates the stability-traction control disabled indicator (sliding car OFF icon) and communicates traction control system status to the BCM over the MS-CAN , the BCM then relays the message to the ABS module over the HS-CAN. The ABS module takes no further action in regards to traction control until the driver activates the system or until the ignition is cycled from OFF to ON.

The ABS module disables traction control if there are any wheel speed sensor or solenoid valve Diagnostic Trouble Codes (DTCs) present in the ABS module. Traction control is also disabled if there is a communication error between the ABS module and the PCM . When traction control is disabled, the ABS module sends a message to the BCM over the HS-CAN . The BCM relays this message to the IPC over the MS-CAN to illuminate the stability-traction control disabled indicator (sliding car OFF icon).