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 can be output to the hybrid vehicle control ECU assembly through the operation of this switch.
      +RES Switch Acceleration and resuming of a preset speed can be performed by operating this switch. A signal is output to the hybrid vehicle control ECU assembly when this switch is operated.
      -SET Switch Deceleration and vehicle speed setting resume signals are output to the hybrid vehicle control ECU assembly due to operation of this switch.
      Hybrid Vehicle 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 hybrid vehicle control ECU assembly.
      ECM Actuates the throttle control motor in accordance with the signals from the hybrid vehicle control ECU assembly.
      Brake Booster with Master Cylinder Assembly Skid Control ECU Transmits the VSC operation signal to the hybrid vehicle control ECU assembly.
      Combination Meter Assembly Multi-information Display Cruise Control Indicator

      • Based on a cruise control indicator operation signal sent by the hybrid vehicle control ECU assembly, the combination meter assembly illuminates the cruise control indicator 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 hybrid vehicle control ECU assembly, the combination meter assembly turns off the cruise control indicator if a malfunction occurs in the cruise control system.
      Cruise Control SET Indicator 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 hybrid vehicle control ECU assembly.
      Hybrid Vehicle Transaxle Assembly MG2 Generates motive force for the wheels in conjunction with the engine.
      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 the 4 wheels.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression degree and outputs it to the hybrid vehicle control ECU assembly.
      Shift Lever Position Sensor Shift Sensor Detects the shift position and transmits signals to the hybrid vehicle control ECU assembly.
      Select Sensor
      Stop Light Switch Assembly Detects the brake pedal being depressed and transmits its signal to the hybrid vehicle control ECU assembly.

  2. FUNCTION


    1. The cruise control has the following control functions:

      Function Outline
      Constant Speed Control The hybrid vehicle control ECU assembly compares the actual vehicle speed with the set speed. If the vehicle speed is higher than the set speed, the hybrid vehicle control ECU assembly 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 assembly 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 hybrid vehicle control ECU assembly stores the vehicle speed, illuminates the cruise control SET indicator on the multi-information display 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 driving 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 that the vehicle is traveling at 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 was being driven at the time the switch was 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 approximately 5 km/h (3 mph), the set vehicle speed will not change.
      RES Switch Control If the cruise control is canceled for any reason other than a malfunction (except cancellation 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 stored before the cancelation of cruise operation by moving the cruise control switch to the +RES side. The cruise control mode can be resumed even if the vehicle speed drops below the low speed limit, because the speed in memory is not cleared.
      Manual Cancel Control

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


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


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


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


      • VSC operation.
      Automatic Cancel Control

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


      • Stop light switch assembly open or short circuit.

      Furthermore, the master warning light illuminates, the cruise control indicator 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 operation, the speed that is set in memory is cleared and the cruise control is canceled.


      • Malfunction in the hybrid system.

      Furthermore, the operation of the cruise control will be 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 operation, the speed that is set in memory is cleared and the cruise control is canceled.


      • Stop light switch assembly input signal is abnormal.


      • Cancel circuit malfunction.


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

      Furthermore, the master warning light illuminates, the cruise control indicator turns off, and a message indicating a malfunction is 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 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, cruise control speed control operation is canceled.


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

  3. DIAGNOSIS


    1. If a malfunction occurs in the cruise control system during constant speed control operation, the hybrid vehicle control ECU assembly automatically cancels control and turns off both the cruise control indicator and the cruise control SET indicator. At this time, "Check cruise control system" is displayed on the multi-information display. The hybrid vehicle control ECU assembly 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.