System Operation: AdvanceTrac

WARNING: This page is about a different car, the 2017 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The AdvanceTrac system is comprised of the traction control and ESC features.

Traction Control

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 calculates how much engine torque reduction is required to eliminate the wheel slip and sends this torque reduction message along with a traction event message to the GWM over the HS-CAN2. The GWM sends the engine torque reduction message to the PCM over the HS-CAN1 and the traction event message to the IPC over the HS-CAN3. 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). After the vehicle speed exceeds 100 km/h (62 mph), traction control is accomplished only through the PCM torque control.

Traction control can be disabled through the menu in the message center, refer to the Owner's Literature for instructions on disabling traction control. This is independent of the ABS and ESC, which cannot be disabled by the driver. When the driver disables traction control, the IPC communicates traction control status to the GWM along the HS-CAN2. The GWM sends the message to the ABS module along the HS-CAN2. 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.

Traction control is disabled if there is a wheel speed sensor or solenoid valve DTC present in the ABS module. Traction control is also disabled if there is a communication error between the ABS module and the GWM. When traction control is disabled, the ABS module sends a message to the GWM along the HS-CAN2 which gateways the message to the IPC over the HS-CAN3 to illuminate the stability-traction control OFF indicator (sliding car OFF icon).

Electronic Stability Control (ESC)

The ABS module continuously monitors the vehicle motion relative to the intended course. This is done by using sensors to compare the steering wheel sensor messages, yaw rate sensor messages and longitudinal acceleration with the actual vehicle motion. The ABS module determines steering wheel angle using information from the wheel speed sensors, the PSCM and the RCM. Steering angle information is calculated by the PSCM and sent to the ABS module over the HS-CAN2. Vehicle yaw rate and longitudinal acceleration information is sent to the ABS module from the RCM over the HS-CAN2. If the ABS module determines from the inputs the vehicle is unable to travel in the intended direction, the brake pressure to the appropriate brake caliper(s) is modulated 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 reduce vehicle speed to help stabilize the vehicle and sends this torque reduction message, along with an ESC event message, to the GWM over the HS-CAN2. The GWM sends the torque reduction message to the PCM over the HS-CAN1 and the ESC event message to the IPC over the HS-CAN3. 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 this message, it flashes the stability-traction control indicator (sliding car icon).

Once the vehicle instability has been corrected, the ABS module returns the solenoid valves in the HCU to their normal position, deactivates the hydraulic pump motor and stops sending the ESC 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).

ESC does not operate with the transmission in REVERSE. ESC is disabled if there is a wheel speed sensor, stability sensor or steering angle sensor DTC present in the ABS module. ESC is also disabled if there is a communication error between the ABS module and the PSCM or the ABS module and the RCM. When ESC is disabled, the ABS module sends a message to the GWM along the HS-CAN2 which gateways the message to the IPC over the along the HS-CAN3 to illuminate the stability-traction control OFF indicator (sliding car OFF icon).