CRUISE CONTROL SYSTEM DETAILS


  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 ECM through the operation of this switch.
      +RES Switch The accelerate function and resuming of a preset speed can be performed by operating this switch. A signal is output to the ECM when this switch is operated.
      -SET Switch The decelerate function and vehicle speed setting signals are output to the ECM due to operation of this switch.
      ECM Controls all functions of the cruise control system in accordance with the signals from switches, sensors and ECUs.
      TCM*1 Performs downshifts and upshifts according to signals from the ECM.
      Brake Actuator Assembly Skid Control ECU Transmits the VSC operation signal to the ECM.
      Combination Meter Assembly Cruise Control Indicator Light

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

      • Based on a cruise control indicator operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator light in yellow if a malfunction occurs in the cruise control system.*2

      • Based on a cruise control indicator operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator light in yellow if a malfunction occurs in the cruise control system.*3
      Cruise Control SET Indicator Light Illuminates while the cruise control system is controlling vehicle speed.
      Multi-information Display*2 Displays a warning message to alert the driver in accordance with a signal provided by the ECM.
      Combination Meter Assembly Transmits the vehicle speed signal to the ECM.
      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.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression degree and outputs it to the ECM.
      Park/Neutral Position Switch Assembly Detects the shift lever position and transmits signals to the ECM.
      Lower Shift Lever Assembly Transmission Control Switch

      • Detects the shift lever position and transmits signals to the ECM.

      • Informs the ECM of driver upshift or downshift operations in S mode.
      Transmission Shift Switch Assembly*4 Informs the ECM of driver upshift or downshift operations in S mode.
      Stop Light Switch Assembly Detects the brake pedal being depressed and transmits its signal to the ECM.

      *1: Models with 2GR-FE engine

      *2: Models with multi-information display

      *3: Models without multi-information display

      *4: Models with paddle shift switch

  2. FUNCTION


    1. The cruise control has the following control functions.

      Function Outline
      Constant Speed Control The ECM compares the actual vehicle speed and the set speed and if the vehicle speed is lower than the set speed, it uses the throttle control motor to increase the throttle opening.
      Set Control

      • When this system fulfils the following conditions, and the cruise control switch is moved to the -SET side and released, the ECM 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 an approximate speed of between 40 km/h (25 mph) and 200 km/h (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 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 1.6 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 at 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 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 the memory has not been cleared.
      Automatic Transmission Control When the vehicle is cruising uphill, the overdrive may turn off depending on Electronically Control Transmission (ECT) control. After the ECM judges that cruising uphill has ended (based on the throttle valve angle), the overdrive function will turn on again. There may be cases where the overdrive turns off when the ACC or RES switch is used.
      Manual Cancel Control

      • If any of the following signals are sent to the ECM, cruise control speed control operation is canceled accordingly.


        • Shift lever is moved from D to N.

        • When 1st, 2nd or 3rd range is selected in S mode.

        • Stop light switch assembly 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 speed control operation, the speed that is set in memory is cleared and cruise control speed control operation is canceled.


        • Stop light switch assembly open or short circuit

        • Vehicle speed signals will be abnormal.

      Furthermore, the cruise control indicator light will turn 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.*1

      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.*2

      • 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.


        • ETCS-i malfunction

      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 assembly input signal is abnormal

        • Cancel circuit malfunction

      Furthermore, the cruise control indicator light will turn 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 ignition switch is turned off.*1

      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 ignition switch is turned off.*2

      • 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]).

      *1: Models with multi-information display

      *2: Models without 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.

        A01HLZTE02
        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 Assembly


      1. The combination meter assembly provides a cruise control indicator light, cruise control SET indicator light and multi-information display to indicate the condition of the cruise control system.*1

      2. The combination meter assembly provides a cruise control indicator light and cruise control SET indicator light to indicate the condition of the cruise control system.*2

        Condition Multi-information Display*1 A01HM41 A01HLRR
        Set Standby - Illuminates in green Does not illuminate
        Being Controlled - Illuminates in green Illuminates
        System Malfunction A01HM1C

        Turns off*1

        Illuminates in yellow*2

        		 Turns off

    *1: Models with multi-information display

    *2: Models without multi-information display

  5. DIAGNOSIS


    1. If a malfunction occurs in the cruise control system during cruise control operation, the ECM automatically cancels control and turns off both the cruise control indicator light and the cruise control SET indicator light. At this time, "CHECK CRUISE CONTROL SYSTEM" is displayed on the multi-information display. The ECM stores the malfunction in the form of a 5-digit Diagnostic Trouble Code (DTC).*1

    2. If a malfunction occurs in the cruise control system during cruise control operation, the ECM automatically cancels control and illuminates the cruise control indicator light in yellow to inform the driver of the malfunction. At this time, the ECM stores the malfunction in the form of a 5-digit Diagnostic Trouble Code (DTC).*2

    3. The 5-digit DTC can be read by connecting the Techstream to DLC3. For details, refer to the Repair Manual.

      *1: Models with multi-information display

      *2: Models without multi-information display