Rear Sonar System

REAR SONAR SYSTEM

System Description

FUNCTION
With the ignition switch in the ON or START position, power is supplied
- through 10 A fuse [No. 12, located in the fuse block (J/B)]
- to sonar control unit terminal 8,
- through 10 A fuse (No. 51, located in the IPDM E/R)
- to back-up lamp relay terminals 1 and 3.

Ground is supplied
- to sonar control unit terminal 6
- through body grounds B7 and B19.

With the ignition switch in the ON or START position, and the transmission gear selector lever in the R position, power is supplied
- to sonar control unit terminal 5
- from back-up lamp relay terminal 5.

With power and ground supplied, transmission gear selector lever in R position, and the rear sonar system OFF switch ON, the rear sonar system will detect obstacles within 1.8 m (5.9 ft.) of the rear sonar sensors. The vehicle operator is notified of obstacles by varied rate of tone from the sonar buzzer depending on distance of obstacle being sensed.

REAR SONAR SYSTEM OFF SWITCH
With power and ground supplied to the sonar control unit, transmission gear selector lever in R position, the sonar system can be disabled and the sonar buzzer silenced by momentarily pressing the rear sonar system OFF switch. The rear sonar system OFF indicator lamp will be illuminated in the rear sonar system OFF switch.

To disable the rear sonar system, ground is supplied
- to sonar control unit terminal 13
- through rear sonar system OFF switch terminal 1
- through rear sonar system OFF switch terminal 2
- from body grounds M57, M61, and M79.

To light the rear sonar system OFF indicator, power is supplied
- from sonar control unit terminal 4
- to the rear sonar system OFF switch terminal 5.

Ground is supplied
- to the rear sonar system OFF switch terminal 6
- from body grounds M57, M61, and M79.

The rear sonar system and buzzer will be disabled and the rear sonar system OFF indicator will be illuminated until the ignition switch is turned OFF. When the ignition switch is turned ON, the rear sonar system will be enabled. Depressing the rear sonar system OFF switch momentarily will enable the rear sonar system also. Enabling the rear sonar system will cause the rear sonar system OFF indicator to go out.

SONAR BUZZER
With power supplied to the sonar control unit and the transmission gear selector lever in R position, a stationary object that is at least 7.0 cm (2.8 in.) wide and 1.0 m (39.0 in.) tall and that is closer than 1.8 meters (5.9 ft.) will be detected by the rear sonar sensors, causing the sonar buzzer to sound a tone. As the vehicle moves closer to the object, the rate of the tone will increase. When the object is less than 25.0 cm (10 in.) from the rear bumper, the tone will sound continuously.

Power is supplied
- from sonar control unit terminal 7
- to sonar buzzer terminal +.

Ground is supplied
- to sonar buzzer terminal -
- from sonar control unit terminal 3.

REAR SONAR SENSOR
With power and ground supplied to the rear sonar sensors, the sonar sensors transmit a 38.4 kHz ultrasonic signal. This signal is reflected back to the sensor by objects large enough and close enough to be detected. The rear sonar sensors measure the time from the transmitted signal to the time the signal is reflected back and sends this information to the sonar control unit.

Power is supplied
- from sonar control unit terminal 16
- to each rear sonar sensor terminal 1.

Ground is supplied
- to each rear sonar sensor terminal 3
- from sonar control unit terminal 15.

Signal is supplied
- from each rear sonar sensor terminal 2
- to sonar control unit terminals 9, 10, 11 and 12.