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 Main 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.
      Brake Booster with Master Cylinder Assembly Skid Control ECU

      • Transmits the wheel speed signal to the hybrid vehicle control ECU.

      • Transmits the VSC operation signal to the hybrid vehicle control ECU.
      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 hybrid vehicle transaxle assembly in accordance with signals from the hybrid vehicle control ECU.
      Hybrid Vehicle Transaxle Assembly Generates motive force for the front wheels.
      ECM Actuates the throttle control motor in accordance with the signals from the hybrid vehicle control ECU.
      Combination Meter Assembly Cruise Control Indicator Light

      • Based on a cruise control Indicator light operation signal sent by the hybrid vehicle 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 main switch.

      • Based on a cruise control Indicator light operation signal sent by the hybrid vehicle control ECU, the combination meter assembly turns off the cruise control Indicator light if a malfunction occurs in the cruise control system.
      Cruise SET Indicator Light Illuminates while the cruise control system is controlling vehicle speed.
      Multi-information Display

      • Displays a warning message to alert the driver in accordance with a signal provided by the hybrid vehicle control ECU.

      • Displays when a vehicle speed is set.
      Master Warning Light Comes on when there is a malfunction in the system.
      Buzzer If the hybrid vehicle control ECU detects automatic cancel or warning signals while the vehicle is operating under cruise control, this buzzer sounds to inform the driver.
      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 Sensors Detects the wheel speed and transmits signals to the skid control ECU.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression angle and transmits it to the hybrid vehicle control ECU.
      Electric Parking Brake Switch Assembly VSC OFF (TRC OFF) Switch Detects the VSC (TRC) off signal and outputs it to the skid control ECU.
      Shift Lever Position Sensor Detects the shift lever position 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.
      Network Gateway ECU Gateway function of CAN communication.

  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 motor generators, 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 motor generators, and accelerates by adjusting the respective motive forces.
      Set Control

      When this system fulfils the following conditions, and the cruise control main 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 main switch.

      • The vehicle is driving at a speed within the range of approximately 40 to 200 km/h (25 to 125 mph).
      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 system cannot be set below that speed. If the vehicle speed drops below that speed while the cruise control is operating, speed control by the cruise control system will be canceled automatically. However, the set speed is kept in memory.
      COAST Switch Control

      When the cruise control main 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 main 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 main 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 main 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 When the vehicle speed is above the low speed limit, the cruise control system resumes operation (when the cruise control main switch is subsequently moved to the +RES side) to reach the vehicle speed that was set at the time the driver canceled cruise control. Even if the vehicle speed dropped below the low speed limit, the set speed can be resumed after the vehicle speed increases above the low speed limit. Also, If the vehicle speed memory is deleted, the return control cannot be performed.
      Manual Cancel Control

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


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

      • D position circuit in the shift lever position sensor off signal (Shift lever is moved from D to any other position).

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

      • Cruise control main 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 memory is cleared and cruise control speed control operation is canceled.


      • Stop light switch open or short circuit.

      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 main 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, speed control by the cruise control system 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 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 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 main switch. The operation of the cruise control is disabled until the power switch is turned off.

      If the following condition occurs while the cruise control system is controlling vehicle speed, the speed that is stored in memory is cleared and speed control by the cruise control system 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 while the cruise control system is controlling vehicle speed, speed control by the cruise control system is canceled.


      • Vehicle speed decreases below the low speed limit approximately 40 km/h (25 mph).
      Other Cancel Conditions

      • VSC is activated.

      • TRC is activated for a period of time.

      • When the VSC or TRC system is turned off by pressing the VSC OFF switch.

      • Power switch off.

      • Electronically controlled brake system operates while driving with cruise control system controlling vehicle speed.

  3. DIAGNOSIS


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

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