TOYOTA PARKING ASSIST-SENSOR SYSTEM(for 8 Sensor Type) SYSTEM DESCRIPTION


  1. GENERAL


    1. This system uses ultrasonic sensors to detect any obstacles at the corners, front and the rear of the vehicle. The system then informs the driver of the distance between the sensors and obstacles as well as their positions by indicating them on the multi-information display in the combination meter assembly and navigation receiver assembly*1 or radio and display receiver assembly*2 and by sounding a buzzer.


      • *1: w/ Navigation System

      • *2: w/ Audio and Visual System (for Radio and Display Type)

  2. FUNCTION OF COMPONENTS

    Component Function

    Steering Pad Switch Assembly

    - Multi-Function Switch (Clearance Sonar Main Switch)

    		 Operating this switch enables, disables or cuts off the operation of the TOYOTA parking assist-sensor system.

    No. 1 Ultrasonic Sensor

    No. 2 Ultrasonic Sensor

    No. 3 Ultrasonic Sensor

    No. 4 Ultrasonic Sensor

    		 Detects the distance between the vehicle and an obstacle.
    No. 1 Clearance Warning Buzzer

    • Sounds when the TOYOTA parking assist-sensor system is turned on approximately 2 seconds or more after the ignition switch is turned to ON (does not sound when the TOYOTA parking assist-sensor system is turned on within 2 seconds of the ignition switch being turned to ON).*3

    • Sounds to inform the driver of the distance to an obstacle.

    Combination Meter Assembly

    - Multi-information Display

    • Displays the location of an obstacle and the approximate distance between the vehicle and obstacle.

    • Informs the driver of ultrasonic sensor malfunctions.

    Combination Meter Assembly

    - Clearance Sonar Indicator

    		 Illuminates to inform the driver while the TOYOTA parking assist-sensor system power is on (the ignition switch is ON and the TOYOTA parking assist-sensor system is on).
    Combination Meter Assembly

    • Transmits the vehicle speed signal to the clearance warning ECU assembly.

    • Receives a TOYOTA parking assist-sensor system (clearance sonar main switch) on/off signal from the multi-function switch of the steering pad switch assembly and transmits it to the clearance warning ECU assembly.
    Clearance Warning ECU Assembly

    • Judges the approximate distance between the vehicle and an obstacle based on the signals from the ultrasonic sensors and sends this value to the multi-information display in the combination meter assembly and multi-display in the combination meter assembly.

    • Sounds the buzzer.
    Main Body ECU (Multiplex Network Body ECU) Transmits the destination information to the clearance warning ECU assembly.
    ECM Transmits the shift position signal to the clearance warning ECU assembly.

    • Navigation Receiver Assembly*1


      • Multi-display

    • Radio and Display Receiver Assembly*2


      • Multi-display

    • Receives the display signals from the clearance warning ECU assembly and displays them on the display panel.

    • Transmits the customization information displayed on the multi-display to the clearance warning ECU assembly.

    *1: w/ Navigation System

    *2: w/ Audio and Visual System (for Radio and Display Type)

    *3: The buzzer does not sound when the ignition switch is ON while the TOYOTA parking assist-sensor system is on.

  3. OPERATION EXPLANATION


    1. The operating conditions of each ultrasonic sensor differ according to the installation position as shown in the table below.

      Installation Position Operating Condition
      Front Corner Sensor

      • Ignition switch is ON.

      • TOYOTA parking assist-sensor system is on.

      • Shift lever in any position other than P.

      • Vehicle speed is less than approximately 10 km/h (6.2 mph). The sensors stop operating when the vehicle speed exceeds approximately 15 km/h (9.3 mph), and start operating when the vehicle speed drops below approximately 10 km/h (6.2 mph).
      Front Center Sensor

      • Ignition switch is ON.

      • TOYOTA parking assist-sensor system is on.

      • Shift position is in any position except P or R.

      • Vehicle speed is less than approximately 10 km/h (6.2 mph). The sensors stop operating when the vehicle speed exceeds approximately 15 km/h (9.3 mph), and start operating when the vehicle speed drops below approximately 10 km/h (6.2 mph).
      Rear Corner Sensor

      • Ignition switch is ON.

      • TOYOTA parking assist-sensor system is on.

      • Shift lever is in R.
      Rear Center Sensor

      • Ignition switch is ON.

      • TOYOTA parking assist-sensor system is on.

      • Shift lever is in R.

      When the system operates, the clearance warning ECU assembly transmits ultrasonic waves from the ultrasonic sensors. If these waves encounter an obstacle within one or more of the sensors ranges, the waves are reflected back to the sensors, which transmit them to the clearance warning ECU assembly.

      Based on this information, the clearance warning ECU assembly sends signals to the indicator and No. 1 clearance warning buzzer. The appropriate distance between the vehicle and the obstacle is then indicated, and the buzzer sounds.

      Tech Tips

      Refer to Detection Range Measurement and Display Inspection.

      Click here

  4. COMMUNICATION SIGNALS OF COMPONENTS

    Tech Tips


    • Allocation refers to the process of the clearance warning ECU setting aside IDs for the sensors.

    • The vehicle has the sensors arranged in 2 groups. There is a front series and a rear series. The sensors are connected in a "daisy chain".


    1. Initialization mode:

      An ID is allocated to each sensor and sensor diagnosis is performed.

      A01QP7LC01
      *1 Clearance Warning ECU Assembly *2 No. 1 Ultrasonic Sensor (Front Corner Sensor LH)
      *3 No.1 Ultrasonic Sensor (Front Corner Sensor RH) *4 No.2 Ultrasonic Sensor (Front Center Sensor LH)
      *5 No.2 Ultrasonic Sensor (Front Center Sensor RH) *6 No. 3 Ultrasonic Sensor (Rear Corner Sensor LH)
      *7 No. 3 Ultrasonic Sensor (Rear Corner Sensor RH) *8 No. 4 Ultrasonic Sensor (Rear Center Sensor LH)
      *9 No. 4 Ultrasonic Sensor (Rear Center Sensor RH) - -
      *a Front - -

      1. When the initial check is operating (the ignition switch is ON and the TOYOTA parking assist-sensor system is on), the clearance warning ECU assembly provides power to the first sensors in each series (front corner sensor LH and rear corner sensor LH).

        Tech Tips

        Refer to Self-check Function Inspection (Initial Check).

        Click here

      2. After the power is supplied, the front corner sensor LH and rear corner sensor LH enter standby mode to receive an ID from the ECU. When a certain amount of time has elapsed, the ECU sends an ID allocation signal to these sensors.

      3. The front corner sensor LH and rear corner sensor LH receive the ID allocation signal from the ECU and perform self-diagnosis. When the sensor self-diagnosis is completed, the ECU sends an ID allocation confirmation signal to these sensors.

      4. After the ID allocation confirmation is performed, the ECU provides power to the second sensors in each series (front corner sensor LH and rear corner sensor LH) via the first sensors. In the same manner as the first sensors, the second sensors enter standby mode. When a certain amount of time has elapsed, the ECU sends an ID allocation signal to the second sensors.

      5. The above operation will be repeated until an ID is allocated to the last sensor, which is in front series (front corner sensor RH) and the rear series (rear corner sensor RH). Initialization ends when ID allocation to all ultrasonic sensors is completed.

    2. Detection mode:

      After initialization mode is completed, the system switches into detection mode. In detection mode, the clearance warning ECU assembly sends information request signals and sensor activation signals to the ultrasonic sensors and receives detection result signals from the sensors.


      1. The ECU regularly sends ID signals, information request signals and sensor activation signals to each ultrasonic sensor according to the communication schedule.

      2. When a certain amount of time has elapsed (sensor detection operation is completed), the ECU sends an ID signal to the sensor to receive a detection result signal.

      3. The ultrasonic sensor sends a detection result signal or detection information signal to the ECU.

      4. The above operation is performed repeatedly for each ultrasonic sensor.