TOYOTA PARKING ASSIST-SENSOR SYSTEM

FUNCTION OF MAIN COMPONENTS

The components have the following functions:

Component	Function
Ultrasonic Sensors	Detects the distance between the vehicle and the obstacle.
Clearance Warning ECU Assembly*1	Judges the approximate distance between the vehicle and obstacle based on the signals from the ultrasonic sensors and sends the buzzer signal to the clearance warning buzzer. Transmits signals to the clearance warning indicator assembly.
Parking Assist ECU*2	Judges the approximate distance between the vehicle and obstacle based on the signals from the ultrasonic sensors and sends the buzzer signal to the clearance warning buzzer. Receives signals from switch operation and the ECU, and displays a clearance warning icon on the combination meter assembly and multi display.
Clearance Warning Buzzer Assembly	Sounds intermittently to inform the driver that the clearance warning ECU assembly has detected an obstacle within the prescribed range.
Multi-information Switch*3	The TOYOTA parking assist-sensor system can be turned on or off by operating this switch.
Back Sonar or Clearance Sonar Switch Assembly*4	Turns the TOYOTA parking assist-sensor system on/off.
Combination Meter Assembly	Transmits received vehicle speed signals to the clearance warning ECU assembly1 or parking assist ECU2. Displays the detection location on the multi-information display when an obstacle is detected.*3
Multi Display Assembly*5	Displays the detection location on the multi display when an obstacle is detected.
Clearance Warning Indicator Assembly*6	Flashes the indicator light of the detected area when an obstacle is detected.
Back-up Light Switch Assembly*7	Transmits the on/off signals of the back-up light switch assembly to the ECM.
Air Conditioning Amplifier Assembly	Transmits the outside air temperature to the clearance warning ECU.
Park/Neutral Position Switch Assembly*8	Transmits the R position signal to the ECM or the TCM*7.
TCM*9	Transmits shift position signals to the ECM.
ECM	Transmits shift position signals from the back-up light switch assembly or park/neutral position switch assembly to the clearance warning ECU assembly1 or parking assist ECU2.

*1: Models with 4-sensor type or 8-sensor type TOYOTA parking assist-sensor system
*2: Models with 8-sensor type TOYOTA parking assist-sensor system
*3: Models with Optitron type combination meter assembly
*4: Models without Optitron type combination meter assembly
*5: Models with navigation system
*6: Models without navigation system
*7: Models with manual transmission
*8: Models with automatic transmission
*9: Models with 1KD-FTV engine

OPERATING CONDITION

The operating condition of each ultrasonic sensor differs in accordance with its installed position as shown in the table below:

Installation Position	Operating Condition
Front Corner*1	Ignition switch (engine switch*2) is ON. Clearance sonar main switch is on. Shift lever is in anything except P. Vehicle speed is approximately 10 km/h (6 mph) or less.
Front Center*1	Ignition switch (engine switch*2) is ON. Clearance sonar main switch is on. Shift lever is in anything except P and R. Vehicle speed is approximately 10 km/h (6 mph) or less.
Rear Center or Corner	Ignition switch (engine switch*2) is ON. Clearance sonar main switch is on. Shift lever is in R.

*1: Models with 8-sensor type TOYOTA parking assist-sensor system
*2: Models with entry and start system

CONSTRUCTION

Ultrasonic Sensor
1. The ultrasonic sensor consists of a circuit portion and a microphone that transmits and receives ultrasonic waves.
2. The circuit portion is filled with urethane to prevent water from entering.
3. The shape of each sensor is identical.
Clearance Warning Buzzer Assembly
1. When the ultrasonic sensor transmits ultrasonic waves and receives the reflected waves from an obstacle, the buzzer sounds in stages in accordance with the distance to the obstacle.
Clearance Warning ECU Assembly
1. The clearance warning ECU assembly effects overall control of the system, including switching between transmission and reception of the ultrasonic sensor signals, processing the received wave signals, determining the presence of obstacles, actuating the clearance warning buzzer assembly, and determining the presence of an open circuit in the sensors.
Clearance Warning Indicator Assembly (Models with 4-sensor Type TOYOTA Parking Assist-sensor System)
1. The driver is informed that there is an obstacle nearby by the flashing of the clearance warning indicator assembly located on the instrument panel. Also, the clearance warning buzzer assembly sounds simultaneously.
  
  Text in Illustration
  
  *1 Clearance Warning Indicator Assembly - -

Text in Illustration
*1	Clearance Warning Indicator Assembly	-	-

OPERATION

After the TOYOTA parking assist-sensor system has started its activation, it sounds the clearance warning buzzer assembly for approximately 1 second, while checking for any malfunction in the ultrasonic sensors.

The on and off times of the clearance warning buzzer assembly vary as shown in the table below, depending on the distance between the obstacle and the ultrasonic sensor.

Front Ultrasonic Sensor*
-		Obstacle Distance [mm (in.)]		Off Time (ms)	On Time (ms)
Detection Area		A	B
Ultrasonic Sensor		Centers	Corners
Detection Lever	1st	Approx. 500 (19.7) to 1000 (39.4)	-	650	150
	2nd	Approx. 375 (14.8) to 500 (19.7)	Approx. 475 (18.7) to 600 (23.6)	150	150
	3rd	Approx. 300 (11.8) to 375 (14.8)	Approx. 350 (13.8) to 475 (18.7)	75	75
	4th	Approx. 300 (11.8) or less	Approx. 350 (13.8) or less	0	Continuous

*: Models with 8-sensor type TOYOTA parking assist-sensor system

Rear Ultrasonic Sensor
-		Obstacle Distance [mm (in.)]		Off Time (ms)	On Time (ms)
Detection Area		C	D
Ultrasonic Sensor		Centers	Corners
Detection Lever	1st	Approx. 650 (25.6) to 1500 (59.0)	-	650	150
	2nd	Approx. 500 (19.7) to 650 (25.6)	Approx. 375 (14.8) to 550 (21.7)	150	150
	3rd	Approx. 400 (15.7) to 500 (19.7)	Approx. 250 (9.8) to 375 (14.8)	75	75
	4th	Approx. 350 (13.8) or less	Approx. 250 (9.8) or less	0	Continuous

Multi-information Display (Models with Optitron Type Combination Meter Assembly)

The items displayed on the multi-information display show the location of an obstacle, the approximate distance between the vehicle and the obstacle, and warning messages relating to a sensor malfunction, sensor freezing, or the presence of dirt on a sensor. When any warning messages are displayed, the master warning light illuminates and the clearance warning buzzer assembly sounds.

The number of lines shown on the display changes based on the actual distance, and the lines flash when the distance is short.

Text in Illustration
*a	Front Corner Sensor LH	*b	Front Center Sensor
*c	Front Corner Sensor RH	*d	Rear Corner Sensor LH
*e	Rear Center Sensor	*f	Rear Corner Sensor RH
*g	Front and Rear Center Sensors	*h	Front and Rear Corner Sensors
*i	Long	*j	Short

Multi Display Assembly (Models with 8-sensor Type TOYOTA Parking Assist-sensor System)
1. The items displayed on the multi display assembly show the location of an obstacle and the approximate distance between the vehicle and the obstacle, warning messages relating to sensor malfunction, sensor freezing, or presence of dirt on the sensor. When any warning messages are displayed, the master warning light illuminates and the clearance warning buzzer assembly sounds.
2. The distance is shown by the number of lines and color based on the actual distance. The display usually illuminates in yellow. When the distance is short, it illuminates in red.
3. The display timing and detection distance on the multi display assembly can be customized.

DIAGNOSIS

If the system cannot activate its detection function due to a malfunction in an ultrasonic sensor, it alerts the driver of the malfunction by the sounding the clearance warning buzzer assembly. For details, refer to the corresponding Repair Manual for this model.

TOYOTA PARKING ASSIST-SENSOR SYSTEM DETAILS