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Home >> Ford >> 2021 >> Bronco Base, 2D Utility, 2.3L Eng VIN H, Part Time T/Case Control, Automatic Trans >> Repair and Diagnosis (Single Page) >> Brakes >> Traction Control >> Anti-Lock Brake System (Abs) And Stability Control >> Description And Operation >> Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description >> System Operation >> AdvanceTrac
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System Operation: AdvanceTrac

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

MyKey Interaction 

Through the MyKey feature, traction control can be configured to be always on or to allow the driver to select the traction control function on or off. When the traction control function is configured to be always on and a MyKey restricted key is in use, the IPC ignores any requests made by the driver to disable the traction control function and does not send any traction control disable messages to the GWM. Refer to the Owner's Literature for additional information on the various MyKey settings.

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 calipers by opening and closing the appropriate solenoid valves while activating the hydraulic pump motor. 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 FD-CAN. The ABS module also sends a traction event message to the GWM over the FD-CAN which relays this 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 deactivates the hydraulic pump motor and solenoid valves, 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 4WD vehicles, the traction control system is disabled by the driver using the stability-traction control switch which is part of the AWDMSS. When the traction control switch is pressed, the ATCM sends a message to the ABS module over the FD-CAN and a message to the IPC through the GWM and over the HS-CAN3. The ABS module takes no further action in regards to traction control until the driver presses the switch again in the same ignition cycle or until the ignition is cycled from OFF to ON. The IPC responds by illuminating the stability-traction control disabled indicator (sliding car OFF icon).

Disabling the traction control system is independent of ABS which cannot be disabled by the driver. 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 GWM over the FD-CAN. The GWM relays this message to the IPC over the HS-CAN3 to illuminate the stability-traction control indicator (sliding car 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 input and the yaw rate sensor input with the actual vehicle motion. The PSCM sends the steering wheel angle information to the ABS module over the FD-CAN. The RCM sends yaw rate sensor and lateral accelerometer information to the ABS module over the HS-CAN2 through the GWM. If the ABS module determines from the inputs the vehicle is unable to travel in the intended direction, it modulates brake pressure to the appropriate brake calipers by opening and closing the appropriate solenoid valves while activating the hydraulic pump motor. At the same time, the ABS module calculates how much engine torque reduction is required to help stabilize the vehicle and sends this torque reduction message to the PCM over the FD-CAN. The ABS module also sends a vehicle stability event message to the GWM over the FD-CAN which relays this 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 vehicle stability event message, it flashes the stability-traction control indicator (sliding car icon).

Once the vehicle instability has been corrected, the ABS module deactivates the hydraulic pump motor and solenoid valves, 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).

ESC does not operate with the transmission in REVERSE or with the transfer case in LOW range. The ABS module disables ESC if there are any wheel speed sensor, stability sensor or steering angle sensor Diagnostic Trouble Codes (DTCs) present in the ABS module. If there is a communication error between the ABS module and the PSCM or the ABS module and the RCM, ESC also is disabled. When ESC is disabled, the ABS module sends a message to the GWM over the FD-CAN. The GWM relays this message to the IPC over the HS-CAN3 to illuminate the stability-traction control indicator (sliding car icon).

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