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 hybrid vehicle 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 hybrid vehicle control ECU when this switch is operated.
      -SET Switch The decelerate function and vehicle speed setting signals are output to the hybrid vehicle control ECU when this switch is operated.
      Hybrid Vehicle Control ECU 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 hybrid vehicle control ECU.
      ECM Actuates the throttle control motor in accordance with the signals from the hybrid vehicle control ECU.
      Brake Booster with Master Cylinder Assembly Skid Control ECU Transmits the VSC operation signal to the hybrid vehicle control ECU.
      Combination Meter Sub-assembly Cruise Control Indicator Light

      • Based on a cruise control indicator light operation signal sent by the hybrid vehicle control ECU, the combination meter sub-assembly illuminates the cruise control indicator light in green 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 light operation signal sent by the hybrid vehicle control ECU, the combination meter sub-assembly illuminates the cruise control indicator light in yellow if a malfunction occurs in the cruise control system.*1

      • Based on a cruise control indicator light operation signal sent by the hybrid vehicle control ECU, the combination meter sub-assembly turns off the cruise control indicator light if a malfunction occurs in the cruise control system.*2
      Cruise SET Indicator Light Illuminates when the vehicle speed is set.
      Multi-information Display*2 Displays a warning message to alert the driver in accordance with a signal provided by the hybrid vehicle control ECU.
      Hybrid Vehicle Transaxle Assembly MG2 Generates motive force for the wheels.
      Throttle Body 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 degree and outputs it to the hybrid vehicle control ECU.
      Shift Lock Control Unit Assembly Shift Lever Position Sensor Detects the shift lever position and transmits signals to the hybrid vehicle control ECU.
      Stop Light Switch Assembly Detects the brake pedal being depressed and transmits its signal to the hybrid vehicle control ECU.

      *1: Models without multi-information display

      *2: Models with multi-information display

  2. FUNCTION


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

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

      When this system fulfills the following conditions, and the cruise control switch is moved to the -SET side and released, the hybrid vehicle 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 running 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 set and working to maintain vehicle speed, 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 km/h or 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 km/h or 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 the vehicle speed is above the low speed limit, the cruise control resumes operation (when the cruise control switch is subsequently pushed to the RES/+ side) to reach the vehicle speed that was set at the time the driver canceled cruise control.
      Manual Cancel Control

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


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

      • Signals indicating a change in the shift state from drive (D) to any other state. (The shift lever is moved from D to N or B.)

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

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

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


      • Stop light switch assembly open or short circuit

      Furthermore, the cruise control indicator light will illuminate in yellow until the cruise control system is turned off using the cruise control switch, and the operation of the cruise control is disabled until the cruise control system is turned on again using the ON-OFF button.*1

      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.*2

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


      • Malfunction in the hybrid system

      Furthermore, the operation of the cruise control is disabled until 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 the memory is cleared and the cruise control is canceled.


      • Stop light switch assembly input signal is abnormal.

      • Cancel circuit malfunction

      • Brake control system malfunction

      • Communication malfunction between the skid control ECU and hybrid vehicle control ECU

      Furthermore, the cruise control indicator light will illuminate in yellow until the cruise control system is turned off using the cruise control switch, and the operation of the cruise control is disabled until the power switch is turned off.*1

      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.*2

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


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

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

      • VSC operation

      *1: Models without multi-information display

      *2: Models with multi-information display

  3. CONSTRUCTION


    1. Cruise Control Switch


      1. The cruise control switch consists of the ON-OFF button and the +RES, -SET and CANCEL switches. The +RES, -SET and CANCEL switches are operated by moving the lever in the 3 directions indicated.

      2. The switches in the cruise control switch are of the automatic reset (normally open) type that turn on only when the switch is being operated and turn off as soon as the driver releases the switch. Furthermore, the functions of the switches are active only when the cruise control system has been turned on using the ON-OFF button on the cruise control switch.

        B005KSEE03
        Text in Illustration
        *1 Cruise Control Switch - -
        *a ON-OFF Button *b +RES Switch
        *c -SET Switch *d CANCEL Switch

  4. OPERATION


    1. Combination Meter Sub-assembly


      1. The combination meter sub-assembly provides a cruise control indicator light and cruise SET indicator light to indicate the condition of the cruise control system.

        Condition Multi-information Display*2 B005KQD B005KUJ
        Set Standby - Illuminates in green Does not illuminate
        Being Controlled B005KS1 Illuminates in green Illuminates
        System Malfunction CHECK CRUISE CONTROL SYSTEM

        Illuminates in yellow*1

        Does not illuminate 2

        		 Does not illuminate

        *1: Models without multi-information display

        *2: Models with multi-information display

  5. DIAGNOSIS


    1. If a malfunction occurs in the cruise control system during cruise control operation, the hybrid vehicle control ECU automatically cancels control and illuminates the cruise control indicator light in yellow*1 or displays a message on the multi-information display*2 to inform the driver of the malfunction. At this time, the hybrid vehicle control ECU stores the malfunction in the form of a Diagnostic Trouble Code (DTC).

      *1: Models without multi-information display

      *2: Models with multi-information display

    2. The DTC can be read when the Global TechStream (GTS) is connected to the DLC3. For details, refer to the Repair Manual.