CRUISE CONTROL SYSTEM(for 2AR-FE) SYSTEM DESCRIPTION

Tech Tips

Refer to Precaution of Cruise Control System for the name of each switch on the cruise control switch.

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  1. GENERAL

    The cruise control system is controlled by the ECM, and vehicle speed control is performed using the throttle body with motor assembly. The ECM controls the following functions: cruise control main switch, - (COAST)/SET, + (ACCEL)/RES (RESUME), CANCEL, vehicle speed operation and shift down control.


    • The ECM compares the vehicle speed from the speed sensors with the stored vehicle speed set using the steering pad switch assembly. The ECM increases the opening angle of the throttle valve when the actual vehicle speed is below the stored vehicle speed, and decreases the opening angle of the throttle body when the actual vehicle speed is more than the stored vehicle speed.

    • The ECM receives signals from the steering pad switch assembly indicating when the cruise control main switch, - (COAST)/SET switch, + (ACCEL)/RES (RESUME) switch, CANCEL switch, etc., is pushed.

    • The ECM illuminates the cruise control indicator in the combination meter assembly when the cruise control system is turned on using the cruise control main switch.

    • The ECM turns off the cruise control indicator in the combination meter assembly and displays a warning message if a malfunction is detected when the cruise control system is controlling vehicle speed.

    • B006YIAC50
      *a Cruise Control Indicator
      *b Cruise SET Indicator

      The ECM illuminates the cruise SET indicator in the combination meter assembly when vehicle speed control begins after the -SET switch is pushed. Also, the ECM displays the current set speed on the multi-information display when the +RES switch or -SET switch is pushed.

  2. FUNCTION OF MAIN COMPONENTS


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

      Component Outline
      Steering Pad Switch Assembly Cruise Control Main Switch Turns the cruise control system on and off.
      CANCEL Switch Outputs a cancel signal to the ECM.
      +RES Switch Outputs acceleration and resume stored speed signals to the ECM.
      -SET Switch Outputs deceleration and set vehicle speed signals to the ECM.
      Skid Control ECU (Brake Actuator Assembly)

      • Sends VSC operation signals to the ECM.

      • Sends TRC operation signals to the ECM.

      • Sends signals such as wheel speed and estimated vehicle acceleration signals to the ECM.
      ECM Controls all functions of the cruise control system in accordance with the signals received from switches, sensors and ECUs.
      Combination Meter Assembly Cruise Control Indicator

      • Illuminates based on signals from the ECM when the cruise control system is turned on using the cruise control main switch.

      • Turns off based on signals from the ECM when a malfunction is detected in the cruise control system.
      Cruise SET Indicator Illuminates when the vehicle speed is set.
      Multi-information Display

      • Displays warning messages to alert the driver.

      • Displays the current set speed.
      Throttle Body with Motor Assembly Throttle Control Motor Adjusts the throttle valve opening angle in accordance with signals received from the ECM.
      Throttle Position Sensor Outputs the throttle valve opening angle to the ECM.
      Speed Sensor Outputs wheel speed signals to the skid control ECU (brake actuator assembly).
      Accelerator Pedal Sensor Assembly Outputs the accelerator pedal depression angle to the ECM.
      Park/Neutral Position Switch Assembly Outputs the shift lever position to the ECM.
      VSC OFF Switch Outputs VSC off signals to the skid control ECU (brake actuator assembly).
      Shift Lock Control Unit Assembly Transmission Control Switch While the vehicle is being driven in S mode, outputs "+" (upshift) or "-" (downshift) request signals to the ECM.
      Stop Light Switch Assembly Outputs brake pedal depressed signals to the ECM.

  3. OPERATION OF CRUISE CONTROL


    1. The cruise control system 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 less than the set speed, it uses the throttle valve motor of the throttle body with motor assembly to increase the throttle valve opening angle.
      Set Control The vehicle speed is stored and speed control is performed when the -SET switch is pushed while driving with the cruise control system on and the vehicle speed is within the set speed range. The current set speed is displayed on the multi-information display when the +RES switch or -SET switch is pushed.
      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.
      High Speed Limit Control The highest possible set speed is approximately 200 km/h (124 mph). The cruise control system cannot be set when the vehicle speed is over the high speed limit. Also, + (ACCEL)/RES (RESUME) cannot be used to increase the speed beyond the high speed limit.
      - (COAST) Control When the cruise control system is controlling vehicle speed and the -SET switch is pushed and held, the cruise control system sends a "throttle valve opening angle 0°" demand signal to the ECM. Following this, the vehicle speed is stored and maintained when the -SET switch is released.
      Tap-down Control When the cruise control system is controlling vehicle speed and the -SET switch is tapped (for approximately 0.6 seconds), the stored vehicle speed decreases by approximately 1 km/h or 1 mph for each time the switch is tapped. When the -SET switch is tapped and the difference between the current and stored vehicle speed is more than 5 km/h (3 mph), the current vehicle speed is stored and speed control is performed.
      + (ACCEL) Control When the cruise control system is controlling vehicle speed and the +RES switch is pushed and held, the cruise control system sends a signal to the ECM to operate the throttle valve motor of the throttle body with motor assembly to open the throttle valve. Following this, the vehicle speed is stored and maintained when the +RES switch is released.
      Tap-up Control When the cruise control system is controlling vehicle speed and the +RES switch is tapped (for approximately 0.6 seconds), the stored vehicle speed increases by approximately 1 km/h or 1 mph for each time the switch is tapped. When the +RES switch is tapped and the difference between the current and stored vehicle speed is more than 5 km/h (3 mph), the stored vehicle speed will not be changed.
      RES (Resume) Control If control of vehicle speed by the cruise control system was canceled due to any of the manual cancel conditions (other than turning the cruise control system off using the cruise control main switch), and if the vehicle speed is between the low and high speed limits, the stored vehicle speed from the time of cancellation will be resumed and maintained when the +RES switch is pushed.
      Manual Cancel Control

      Performing any of the following cancels the cruise control system control of vehicle speed (the stored vehicle speed in the ECM is maintained).


      • Depressing the brake pedal.

      • Moving the shift lever from D or S to any other position.

      • Selecting the S3, S2 or S1 range with the shift lever in S.

      • Pushing the CANCEL switch.

      • Turning the cruise control system off using the cruise control main switch (the stored vehicle speed in the ECM is not maintained).
      Automatic Cancel Control

      This system has an automatic cancellation function (fail-safe).

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