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ESP/BAS control module, task - GF42.45-P-4501-02F

The ESP and BAS control module (N47-5) performs all calculations for performing the control functions of the following control systems:

This results in the following sub tasks:

  1. Recording and processing electrical signals 
    • The ESP and BAS control module (N47-5) detects electrical signals of the system components and then conditions and evaluates these signals.

    A distinction is made with the evaluated data between

    • data for describing the physical parameters and if necessary for calculating other physical parameters that are required for control function calculations
    • and information for describing the status of a switch or sensor.
    1. 1.1 Stop lamp switch (S9/1) 

      Detect and evaluate the position of the dual contact switch (NO contact and NC contact) position when the driver applies the brake, use with ESP control.

    2. 1.2 BAS release switch (A7/7s1) 

      Detect the status of the BAS release switch (A7/7s1). When the BAS release switch (A7/7s1) is not actuated, the BAS solenoid valve is active (A7/7y1) and the brake pedal is not pressed the stop lamps are prevented from coming on.

    3. 1.3 Rpm sensor for left front, right front, left rear, right rear wheels (L6/1, L6/2, L6/3, L6/4) 

      The conditioned wheel speed signals are constantly compared both with each other and with the specified slip thresholds at the front and rear wheels in relation to the speed of the vehicle.

      • Calculating the following values:

        Vehicle speed, acceleration, deceleration, wheel slip, drive slip, decel slip.

    4. 1.4 ESP brake pressure sensor (B34) 
      • Register the actuation of the brake by the driver and record the brake pressure.
      • Calculate the wheel brake forces (longitudinal forces).
      • Calculate the lateral stability (lateral forces) from the existing wheel brake forces (longitudinal forces).

        IMPORTANT Only if

        ESP control is required during brake application.

    5. 1.5 BAS diaphragm travel sensor (A7/7b1) 

      Calculate the pedal speed of the brake pedal.

    6. 1.6 ESP OFF switch (S76/6) 
      • Detect the driver's request to "deactivate ESP" when the driver presses the ESP OFF switch (S76/6). Then
        • the ASR drive torque control
        • and the ESP braking torque control

          are switched off when the vehicle is accelerating and rolling. When the driver applies the brakes the ESP braking torque control remains available up to a vehicle speed of approx. 60 km/h.

    7. 1.7 Yaw rate sensor (B24/9) 
      • Capture the yaw rate of the vehicle about the vertical axis e.g. when the vehicle skids.
      • Calculate the lateral forces that occur when cornering.
      • Detect oversteering or understeering.
    8. 1.8 Left front, right front, left rear brake pad contact sensors (S10/1, S10/2, S10/3) 

      Detect the wear of the brake pads.

    9. 1.9 Steering angle sensor (B24/8) 
      • Register a change in direction or cornering by evaluating the steering angle and the wheel rpm.
      • Register the driver's requirements together with the vehicle speed.
  2. Record and process CAN messages

    Record and evaluate CAN message from other control modules.

    1. 2.1 ME-SFI control module (N3/10) or CDI control module (N39/2) 
      • CAN message "engine torque" 

        Capture the engine torque, required to determine a reduced engine torque.

      • CAN message "accelerator pedal position" 

        Determine the accelerator pedal position, which is used to work out the engine torque requested by the driver.

    2. 2.2 ETC [EGS] control module (N15/3) 
      • CAN message "transmission ratio" 

        Determine which gear is currently engaged. The information is required to calculate the driving power at the drive gears and to control the drive torque.

  3. Output electrical signals and CAN messages 
    • Determine the type of control mode 

      After evaluating the signals and CAN messages that have been read in, the ESP and BAS control module (N47-5) determines the type of control mode (ABS, ETS, BAS or ESP) which defines the output of certain electrical signals or CAN messages.

    • The system components are actuated with an electrical signal according to the type of control mode and data is passed to other control modules using

      CAN messages. The control modules require these CAN message to either perform one of the control functions of the traction systems or to perform other internal tasks.

    1. 3.1 BAS solenoid valve (A7/7y1) 

      Actuate the BAS solenoid valve (A7/7y1) to produce the primary pressure of approx. 5 bar in the brake circuits, which is applied as primary pressure at the intake side of the high pressure and return pumps.

    2. 3.2 Stop lamp suppression relay (K55) 

      Actuate the stop lamp supression relay (K55) which then interrupts the voltage supply of the stop lamp switch (S9/1). This prevents the stop lamps from switching on.

    3. 3.3 Traction system hydraulic unit (A7/3) 
      • Actuate the solenoid valves with the calculated actuation times to produce the calculated specified values for the brake pressures
      • as well as the high pressure and return pumps of the traction system hydraulic unit (A7/3).
    4. 3.4 Instrument cluster (A1) 

      Pass CAN messages with information for actuating

      • the ABS indicator lamp (A1e17)
      • and the ABS/ESP/4-ETS warning lamp (A1e36).
    5. 3.5 Motor electronics control module (N3/10) or CDI control module (N39/2) 
      • CAN message "drive torque" 

        Calculate and transfer the CAN message with the specified value for the drive torque.

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