GENERAL INFORMATION


FEATURES




  • ASTC is a system combining the functions of Active Stability Control System (ASC) and Active Traction Control System (ATC).
  • When ATC detects the slip of the driving wheel (ex. during startup on low mu road), it automatically applies the brakes to the slipping driving wheel. At the same time, ATC reduces the engine output and prevents the wheel spin when it determines that the engine torque is too high for the road surface mu.
  • When the ASC determines that the vehicle is in a dangerous condition, it reduces the engine output and applies brake force to four wheels independently to control the vehicle behaviour, avoiding the critical state.
  • Fail-safe function ensures safety is maintained
  • Improved serviceability
  • To shorten the lines and enhance data transmission reliability, communication with other ECU is performed over a CAN (Controller Area Network).
    note For further details on CAN communication, refer to GROUP 54C, CAN .
    note On vehicles with ASC, the ASTC-ECU controls ABS as well.

CONSTRUCTION DIAGRAM




Component
 No.
 Function
Sensor

 Wheel speed sensor
 1
 Sends current pulse signals at frequencies which are proportional to the rotation speeds of each wheel to the ASTC-ECU.
Stop lamp switch
 2
 Sends a signal to the ASTC-ECU to indicate whether the brake pedal is depressed or not.
G and yaw rate sensor
 3
 It detects the lateral acceleration, and yaw rate of the vehicle. Then it sends a signal through the CAN bus line to the ASTC-ECU.
Steering wheel sensor
 4
 Detects the steering wheel angle, and sends a signal to the ASTC-ECU through the CAN bus line.
ASC switch
 5
 Sends a signal to the ASTC-ECU to turn on and off the traction control.
Pressure sensor
 6
 Is incorporated in the hydraulic unit, and informs the ASTC-ECU of the brake fluid pressure in the master cylinder.
Actuator
 Hydraulic unit
 7
 Drives the solenoid valves according to signals from the ASTC-ECU in order to control the brake hydraulic pressure for each wheel.
Brake warning lamp
 8
 Illuminates in response to signals from the ASTC-ECU when a malfunction happens in the system.
ABS warning lamp
 9
 Illuminates in response to signals from the ASTC-ECU when a problem develops in the system.
ASTC indicator lamp
 10
 Receives a signal from the ASTC-ECU, and flashes to inform the driver that the system is operating, or illuminates to inform the driver of system failure.
ASTC OFF indicator lamp
 11
 Receives a signal from the ASTC-ECU, and illuminates to inform the driver that the system is not operating or defective, or flashes to inform system over heat.
Diagnosis connector
 12
 Sets the diagnosis codes and allows communication with the M.U.T.-III.
A/T-ECU*
 13
 Receives a signal from the ASTC-ECU to control the engine output.
Engine-ECU
 14
 Receives a signal from the ASTC-ECU to control the engine output.
Active Stability & Traction Control System control unit (ASTC-ECU)
 15
 Controls actuators (described above) based on the signals coming from each sensor.
Controls the self-diagnostics and fail-safe functions.
Controls the diagnostic function (M.U.T.-III compatible).
note *Vehicles for A/T