Toyota Parking Assist-Sensor System System Description

Body Electrical. Camry. Acv40 Gsv40
Park Assist Monitoring. Camry. Acv40 Gsv40

  1. GENERAL

  1. FUNCTION OF COMPONENTS

  1. OPERATION EXPLANATION

  1. COMMUNICATION SIGNAL OF COMPONENTS

Toyota Parking Assist-Sensor System -- System Description



GENERAL

  1. This system uses ultrasonic sensors to detect any obstacles at the corners and the rear of the vehicle. The system then informs the driver of the distance between the sensors and the obstacles as well as their positions by indicating them on the multi-information display and by sounding a buzzer.


FUNCTION OF COMPONENTS

Components
Function
Ultrasonic sensor (6)
Detects the distance between the vehicle and an obstacle
Clearance warning buzzer
Sounds the buzzer to inform the driver according to the distance to the obstacle
Multi-information display on the combination meter
Transmits a vehicle speed signal to the clearance warning ECU.
  1. Displays the location of the obstacle and the approximate distance between the vehicle and the obstacle.
  2. Informs the driver if the ultrasonic sensors malfunction, or if they are frozen or dirty
Clearance sonar main switch
Operating this switch allows the operation of the clearance sonar system to be enabled or disabled.
Clearance warning ECU
Judges the approximate distance between the vehicle and the obstacle based on the signals from the ultrasonic sensors and sends it to the multi-information display.
Sounds the clearance warning buzzer.
ECM
Transmits a shift position signal to the clearance warning ECU
A/C amplifier
Transmits the ambient temperature display signal to the clearance ECU

OPERATION EXPLANATION

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

    Installation Position
    		Operating Condition
    Front Corner Sensor
    1. Ignition switch is on (IG).
    2. Clearance sonar main switch is ON.
    3. Shift position is not P.
    4. Vehicle speed is approx. 10 km/h (6.2 mph) or less. The sensor stops operating when the vehicle speed exceeds 15 km/h (9.3 mph), and starts operating when the vehicle speed drops to below 10 km/h (6.2 mph). (state of vehicle is forward.)
    Rear Corner Sensor
    1. Ignition switch is on (IG).
    2. Clearance sonar main switch is ON.
    3. Shift position is R.
    Rear Center Sensor
    1. Ignition switch is on (IG).
    2. Clearance sonar main switch is ON.
    3. Shift position is R.

COMMUNICATION SIGNAL OF COMPONENTS
HINT:
  1. Allocation refers to the process of the clearance warning ECU setting aside IDs for the sensors.
  2. 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.


    Camry. Acv40 Gsv40.Park Assist Monitoring.Toyota Parking Assist-Sensor System.Toyota Parking Assist-Sensor System System Description


    1. When the initial check is operating (the ignition switch turn to ON and the clearance sonar main switch is on), the clearance warning ECU provides power to the first sensors in each series (front left sensor and rear right sensor).

      HINT:
      Refer to Self-check Function Inspection (Link).

    2. After the power is supplied, the front left sensor and rear right sensor 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 left sensor and rear right sensors receive the ID allocation signal from the ECU and perform self-diagnosis. When the sensor self-diagnosis is complete, the ECU sends an ID allocation confirmation signal to the sensors.

    4. After the ID allocation confirmation is performed, the ECU provides power to the second sensors in each series (front right sensor and rear right center sensor) via the first sensors. In the same manner as the first sensors, the second sensors enter the 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 the rear series (rear left sensor). Initialization ends when ID allocation to all ultrasonic sensors is complete.

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

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

    2. When a certain amount of time has elapsed (sensor detection operation is complete), the clearance warning 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 repeatedly performed for each ultrasonic sensor.