CRUISE CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components in the cruise control system have the following functions:

      Component Function
      Cruise Control Switch ON-OFF Button Turns the cruise control system on and off.
      CANCEL Switch A cancel signal is output to the power management control ECU when this switch is operated.
      +RES Switch The accelerate function and resuming of a preset speed can be performed by operating this switch. A signal is output to the power management control ECU when this switch is operated.
      -SET Switch The decelerate function and vehicle speed setting signals are output to the power management control ECU due to operation of this switch.
      Power Management Control ECU Assembly Controls all functions of the cruise control system in accordance with the signals from switches, sensors and ECUs.
      Inverter with Converter Assembly MG ECU Built into the inverter with converter assembly. Controls the motive force of MG2 in accordance with signals from the power management control ECU.
      Hybrid Vehicle Transmission Assembly MG2 Generates motive force for the wheels.
      Skid Control ECU Assembly Transmits the VSC operation signal to the power management control ECU.
      ECM Actuates the throttle control motor in accordance with the signals from the power management control ECU.
      Combination Meter Assembly Cruise Control Indicator Light

      • Based on a cruise control indicator operation signal sent by the power management control ECU, the combination meter assembly illuminates the cruise control indicator light when the cruise control system has been turned on using the ON-OFF button on the cruise control switch.

      • Based on a cruise control indicator operation signal sent by the power management control ECU, the combination meter assembly turns off the cruise control indicator light if a malfunction occurs in the cruise control system.
      Cruise Control SET Indicator Light Illuminates when the vehicle speed is set.
      Multi-information Display Displays a warning message to alert the driver in accordance with a signal provided by the power management control ECU.
      Throttle Body with Motor Assembly Throttle Control Motor Adjusts the throttle valve opening angle in accordance with signals from the ECM.
      Throttle Position Sensor Detects the throttle valve opening angle and outputs it to the ECM.
      Speed Sensor Detects the wheel speed of each of the 4 wheels.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression angle and transmits it to the power management control ECU.
      Shift Lever Position Sensor Detects the shift lever position and transmits signals to the power management control ECU.
      Shift Paddle Switch (Transmission Shift Switch Assembly) Informs the power management control ECU of driver upshift or downshift operations.
      Combination Switch Assembly VSC OFF Switch Detects the VSC off signal and outputs it to the skid Control ECU assembly.
      Transmission Floor Shift Assembly Transmission Control Switch

      • Detects the shift lever position and transmits signals to the power management control ECU.

      • Informs the ECM of driver upshift or downshift operations while the shift lever is in S.
      Stop Light Switch Assembly Detects the brake pedal being depressed and transmits its signal to the power management control ECU.

  2. FUNCTION


    1. The cruise control system has the following control functions:

      Function Outline
      Constant Speed Control The power management control ECU compares the actual vehicle speed with the set speed. If the vehicle speed is higher than the set speed, the power management control ECU calculates optimal motive forces for the engine and MG2, and decelerates by adjusting the respective motive forces. If the vehicle speed is lower than the set speed, the power management control ECU calculates optimal motive forces for the engine and MG2, and accelerates by adjusting the respective motive forces.
      Set Control

      When this system fulfils the following conditions, and the cruise control switch is moved to the -SET side and released, the power management control ECU stores the vehicle speed and maintains the vehicle constantly at that speed.


      • The cruise control system has been turned on using the ON-OFF button on the cruise control switch.

      • The vehicle is being driven at a speed of approximately 40 km/h (25 mph) or more
      Low Speed Limit Control The low speed limit is the lowest speed that cruise control can be set at and it is designed to be approximately 40 km/h (25 mph). The cruise control cannot be set below that speed. If the vehicle speed drops below that speed while the cruise control is operating, the cruise control will be canceled automatically. However, the set speed is kept in memory.
      COAST Switch Control

      When the cruise control switch is held to the -SET side, the vehicle speed and the set vehicle speed change as follows:


      • The vehicle will decelerate.

      • The set vehicle speed will change to the speed at which the vehicle is being driven when the COAST switch (-SET side operation) is released.
      Tap Down Control

      When the cruise control switch is moved momentarily (approximately 0.6 seconds or less) to the -SET side, the vehicle speed and the set vehicle speed change as follows:


      • The vehicle will decelerate in increments of approximately 1.6 km/h (1 mph) each time the switch is moved.

      • However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will change to the speed at which the vehicle is being driven when the switch is pushed.
      ACC Switch Control

      When the cruise control switch is held to the +RES side, the vehicle speed and the set vehicle speed change as follows:


      • The vehicle will accelerate.

      • The set vehicle speed will change to the speed at which the vehicle is being driven when the switch is released.
      Tap Up Control

      When the cruise control switch is moved momentarily (approximately 0.6 seconds or less) to the +RES side, the vehicle speed and the set vehicle speed change as follows:


      • The vehicle will accelerate in increments of approximately 1.6 km/h (1 mph) each time the switch is moved.

      • However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will not change.
      RES Switch Control If cruise control speed control operation is canceled for any reason other than a malfunction (except cancelation by operating the ON-OFF button on the cruise control switch) and the vehicle speed is more than the low speed limit, the vehicle can be returned to the speed which was stored before the cancelation of cruise control operation by moving the cruise control switch to the +RES side. The stored vehicle speed can be resumed even if the vehicle speed drops below the low speed limit, because the speed in memory has not been cleared.
      Manual Cancel Control

      If any of the following signals are sent to the power management control ECU, cruise control speed control operation is canceled accordingly.


      • Stop light switch on signal (The brake pedal is depressed).

      • Signals indicating that the shift lever has been moved from D or S to other position. (The shift lever is moved from D to N or S ).

      • CANCEL switch on signal (The cruise control switch is moved to the CANCEL side).

      • Cruise control switch (ON-OFF button) off signal.

      • TRC operates for a certain period of time during cruise control driving.

      • VSC operation.
      Automatic Cancel Control

      • If the following condition occurs during cruise control speed control operation, the speed that is stored in memory is cleared and cruise control speed control operation is canceled.


        • Stop light switch open or short circuit.

        • Vehicle speed signals are abnormal.

        • Furthermore, the master warning light illuminates, cruise control indicator light turns off, and a message indicating a malfunction will be displayed on the multi-information display until the cruise control system is turned off using the cruise control switch. The operation of the cruise control is disabled until the cruise control system is turned on again using the ON-OFF button.


      • If the following condition occurs during cruise control speed control operation, the speed that is set in memory is cleared and cruise control speed control operation is canceled.


        • Malfunction in the hybrid system.

        • Furthermore, the operation of the cruise control is disabled until the cruise control system is turned on again using the ON-OFF button.


      • If any of the following conditions occur during cruise control speed control operation, the speed that is set in memory is cleared and cruise control speed control operation is canceled.


        • Stop light switch input signal is abnormality.

        • Cancel circuit malfunction.

        • Communication malfunction between the skid control ECU assembly and power management control ECU.

        • Brake control system malfunction.

        • Furthermore, the master warning light illuminates, cruise control indicator light turns off, and a message indicating a malfunction will be displayed on the multi-information display until the cruise control system is turned off using the cruise control switch. The operation of the cruise control is disabled until the power switch is turned off.


      • If the following condition occurs during cruise control speed control operation, the speed that is set in memory is cleared and cruise control speed control operation is canceled.


        • Vehicle speed decreases by 16 km/h (10 mph) or more below the speed at which the cruise control is set.


      • If the following condition occurs during cruise control speed control operation, cruise control speed control operation is canceled.


        • Vehicle speed decreases below the low speed limit (approximately 40 km/h [25 mph]).

  3. DIAGNOSIS


    1. If a malfunction occurs in the cruise control system during cruise control operation, the power management control ECU cancels cruise control operation, illuminates the master warning light and turns off the cruise control indicator light and cruise control SET indicator light. At this time, "Check Cruise Control System" is displayed on the multi-information display. The power management control ECU stores the malfunction in the form of a 5-digit Diagnostic Trouble Code (DTC).

    2. The 5-digit DTC can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.