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System Description

  1. CRUISE CONTROL SYSTEM 

    This system is controlled by the power management control ECU, and control is performed using the throttle position sensor and motor. The power management control ECU controls the following functions: ON-OFF, - (COAST)/SET, + (ACCEL)/RES (RESUME), CANCEL, vehicle speed operation and shift down control.

    • The power management control ECU compares the vehicle speed from the speed sensor with the stored vehicle speed set using the cruise control switch. The power management control ECU instructs the throttle valve motor of the throttle body with motor assembly to close the valve when the vehicle speed is greater than the stored speed, and instructs it to open the valve when the vehicle speed is less than the stored speed.
    • The power management control ECU receives signals such as ON-OFF, - (COAST)/SET, + (ACCEL)/RES (RESUME), and CANCEL from the cruise control switch and executes the command.
    • The power management control ECU illuminates the combination meter sub-assembly cruise control indicator light when the cruise control system is turned on using the cruise control switch (ON-OFF button).
    • The power management control ECU blinks the combination meter sub-assembly when a malfunction occurs during cruise control driving.
      • Fig 1: Identifying SET Indicator
      GTY212153Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    • The power management control ECU illuminates the combination meter sub-assembly cruise control SET indicator light when vehicle speed control begins after the cruise control switch is pushed to -/SET while driving.
      TEXT IN ILLUSTRATION

      *1 Cruise Control Indicator Light
      *2 Cruise Control SET Indicator
    • The power management control ECU cancels control of vehicle speed when the brake pedal is depressed and the power management control ECU receives a signal from the stop light switch assembly.
    • The power management control ECU cancels control of vehicle speed when the shift lever is moved from D to any other position.
    • The power management control ECU cancels control of vehicle speed when the cruise control switch is pulled to CANCEL.
    • The power management control ECU cancels control of vehicle speed when the cruise control system is turned off using the cruise control switch (ON-OFF button).
  2. LIMIT CONTROL 
    1. Low speed limit

      The lowest possible set speed is approximately 40 km/h (25 mph). The cruise control system cannot be set when the vehicle speed is below the low speed limit. Control of vehicle speed will be automatically canceled but the stored vehicle speed will be retained when the vehicle speed drops below the low speed limit while the cruise control is controlling vehicle speed.

    2. High speed limit

      The highest possible set speed is approximately 200 km/h (125 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.

  3. OPERATION OF CRUISE CONTROL 

    The cruise control switch is used to turn the cruise control system on and off, as well as operate 7 functions: SET, - (COAST), TAP-DOWN, RES (RESUME), + (ACCEL), TAP-UP, and CANCEL. The SET, TAP-DOWN, and - (COAST) functions, and the RES (RESUME), TAP-UP, and + (ACCEL) functions are operated with the same switch. The cruise control switch is an automatic return type switch which turns on only while operating it in the direction of each arrow, and turns off after it is released.

    1. SET CONTROL

      The vehicle speed is stored and speed control begins when the cruise control switch is pushed to -/SET while driving with the cruise control system on (while the cruise control indicator light is illuminated), and the vehicle speed is within the set speed range (between the low and high speed limits).

    2. - (COAST) CONTROL

      When the cruise control system is controlling vehicle speed and the cruise control switch is pushed to -/SET and held in that position, the cruise control system sends a "throttle valve opening angle 0°" demand signal to the power management control ECU. Following this, the vehicle speed is stored and maintained when the cruise control switch is released.

      HINT: 

      An actual throttle valve opening angle of 0° is not possible due to items such as idle speed control.

    3. TAP-DOWN CONTROL

      When the cruise control system is controlling vehicle speed and the cruise control switch is tapped to the -/SET side (for approximately 0.6 seconds), the stored vehicle speed decreases by approximately 1.6 km/h (1.0 mph) for each time the switch is tapped. When the cruise control switch is tapped to -/SET and the difference between the current and stored vehicle speed is more than 5 km/h (approximately 3 mph), the current vehicle speed is stored and speed control is performed.

    4. ACCELERATION CONTROL

      When the cruise control system is controlling vehicle speed and the cruise control switch is pushed to +/RES and held in that position, the cruise control system sends a signal to the power management control ECU 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 cruise control switch is released.

    5. TAP-UP CONTROL

      When the cruise control system is controlling vehicle speed and the cruise control switch is tapped to the +/RES side (for approximately 0.6 seconds), the stored vehicle speed increases by approximately 1.6 km/h (1.0 mph) for each time the switch is tapped. When the cruise control switch is tapped to +/RES and the difference between the current and stored vehicle speed is more than 5 km/h (approximately 3 mph), the stored vehicle speed will not be changed.

    6. RESUME CONTROL

      If cruise control system control of vehicle speed was canceled due to any of the manual cancel conditions (other than turning the cruise control system off using the ON-OFF switch), and if the vehicle speed is between the low and high speed limits, the stored vehicle speed from the time of cancelation will be resumed and maintained when the cruise control switch is pushed to +/RES.

    7. MANUAL CANCEL CONTROL

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

      • Depressing the brake pedal.
      • Moving the shift lever from D to any other position.
      • Pulling the cruise control switch to CANCEL
      • Turning the cruise control system off using the cruise control switch (ON-OFF button) (the stored vehicle speed in the power management control ECU is not maintained).
  4. AUTO CANCEL (FAIL-SAFE) 

    This system has an automatic cancellation function (fail-safe). Refer to FAIL-SAFE CHART .

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