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 SASM  sends the steering wheel angle and rate of change information to the ABS  module over the High Speed Controller Area Network (HS-CAN) while the RCM  sends yaw rate sensor information to the ABS  module over a private High Speed Controller Area Network (HS-CAN). If the ABS  module determines from the inputs that the vehicle is unable to travel in the intended direction, it modulates brake pressure to the appropriate brake caliper(s) or wheel cylinder(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 reduce vehicle speed to help stabilize the vehicle and sends this torque reduction message to the PCM  over the High Speed Controller Area Network (HS-CAN). The ABS  module also sends a traction event message to the BCM  over the High Speed Controller Area Network (HS-CAN), the BCM  relays the traction event message to the IPC  over the Medium Speed Controller Area Network (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 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 traction event and torque reduction messages. The PCM  returns engine timing and fuel injectors to normal operation and the IPC  extinguishes the sliding car icon.

On vehicles equipped with a 2.0L Gasoline Turbocharged Direct Injection (GTDI) engine, the Electronic Stability Control (ESC) function can be disabled by the driver through the Electronic Stability Control (ESC) OFF switch. Pressing the switch once disables the traction control function and reduces the amount of Electronic Stability Control (ESC) intervention. Pressing and holding the switch for 5 seconds disables both traction control and the Electronic Stability Control (ESC). The system remains in the selected state until the driver enables the systems with a single press of the Electronic Stability Control (ESC) OFF switch or until the ignition is cycled from OFF to ON.

The Electronic Stability Control (ESC) function does not operate with the transmission in REVERSE. The Electronic Stability Control (ESC) function is disabled if there are any wheel speed sensor, stability sensor or steering angle sensor Diagnostic Trouble Codes (DTCs) present in the ABS  module. Also, if there is a communication error between the ABS  module and the SASM  or the RCM  , the Electronic Stability Control (ESC) function is disabled. When the Electronic Stability Control (ESC) function is disabled, due to driver selection, Diagnostic Trouble Codes (DTCs) or a loss of communication, the ABS  module sends a message to the BCM  which relays the message to the IPC  over the Medium Speed Controller Area Network (MS-CAN) to illuminate the sliding car OFF icon.