Electronic Stability Control (ESC)

The Anti-Lock Brake System (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 that of the actual vehicle motion. The Steering Column Control Module (SCCM) (vehicles with active park assist) or Power Steering Control Module (PSCM) (vehicles without active park assist) sends the steering wheel angle and rate of change information to the Anti-Lock Brake System (ABS) module over the High Speed Controller Area Network (HS-CAN) while the Restraints Control Module (RCM) sends yaw rate sensor information to the Anti-Lock Brake System (ABS) module over a private High Speed Controller Area Network (HS-CAN). If the Anti-Lock Brake System (ABS) module determines from the inputs that the vehicle is unable to travel in the intended direction, the Anti-Lock Brake System (ABS) module modulates brake pressure to the appropriate brake caliper(s) by opening and closing the appropriate solenoid valves inside the Hydraulic Control Unit (HCU) while the hydraulic pump motor is activated. At the same time, the Anti-Lock Brake System (ABS) module sends a message over the High Speed Controller Area Network (HS-CAN) that a vehicle stability event is taking place. When the Powertrain Control Module (PCM) receives this message, it assists with vehicle control by adjusting engine timing and decreasing fuel injector pulses. When the Instrument Panel Cluster (IPC) receives this message, it flashes the stability/traction control indicator (sliding car icon). Once the vehicle instability has been corrected, the Anti-Lock Brake System (ABS) module returns the solenoid valves in the Hydraulic Control Unit (HCU) to their normal position, deactivates the hydraulic pump motor and sends another message over the High Speed Controller Area Network (HS-CAN) bus indicating that the event has ended. The Powertrain Control Module (PCM) returns engine timing and fuel injectors to normal operation and the Instrument Panel Cluster (IPC) extinguishes the sliding car icon.

The Electronic Stability Control (ESC) function does not operate with the transmission in REVERSE. The Anti-Lock Brake System (ABS) module disables the Electronic Stability Control (ESC) function if there are any wheel speed sensor, stability sensor or steering angle sensor Diagnostic Trouble Codes (DTCs) present in the Anti-Lock Brake System (ABS) module. Also, if there is a communication error between the Anti-Lock Brake System (ABS) module and the Power Steering Control Module (PSCM), the Steering Column Control Module (SCCM) or the Restraints Control Module (RCM) the Electronic Stability Control (ESC) function is disabled. When the Electronic Stability Control (ESC) function is disabled, the Anti-Lock Brake System (ABS) module sends a message over the High Speed Controller Area Network (HS-CAN) to the Instrument Panel Cluster (IPC) to illuminate both the sliding car icon and the stability/traction control disabled indicator (sliding car OFF icon).