Object Detection Description and Operation (UD7 with Parking Assist Indicator)

Object Detection Description and Operation (UD7 with Parking Assist Indicator)

The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicle's path when reversing at speeds of less than 8 km/h (5 MPH). The distance and location of the object is determined by 4 object sensors located in the rear bumper. The parking assist system will notify the driver using the parking assist indicators and an audible beep signal through the radio.

The rear parking assist system is made up of the following components:

* Parking assist control module
* Rear object alarm sensors
* Parking assist indicator
* Parking assist switch
* Parking assist switch indicator

Parking Assist Control Module

The parking assist control module provides an 8 V reference and a low reference to the four rear parking assist sensors. The parking assist control module receives individual signals from each of the four sensors and determines the location and distance of an object based on these inputs. When an object is detected, the parking assist control module will illuminate the appropriate LED on the parking assist indicator and send a serial data message to the radio requesting an audible alert.

Rear Object Alarm Sensors

The rear object alarm sensors are located the in rear bumper of the vehicle. The sensors are used to determine the distance between an object and the rear bumpers. Each sensor emits an ultrasonic frequency which is reflected off object located behind the vehicle. These reflections are received by the sensors. The time difference between when the frequency was emitted and when the reflection is received, known as sensor echo time, is used to determine the distance to the object. The sensors report this information to the parking assist control module.

Parking Assist Indicator

The parking assist indicator is located in the interior rear of the vehicle and is visible through the inside rearview mirror. The indicator contains three LEDs: two amber and one red. The parking assist control module controls these three LEDs as a visual indicator of how close the vehicle bumper is to an object. The parking assist control module supplies voltage to each of the LEDs and commands each LED on by supplying an individual ground.

Parking Assist Switch

The parking assist can be activated and deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

Parking Assist Switch Indicator

The indicator in the parking assist switch shows the status of the parking assist. If the lamp is ON, the parking assist is activated.

Rear Parking Assist Operation

When the vehicle is first placed into reverse, the rear parking assist system performs a bulb check. During the bulb check, the all three LED located in the parking assist indicator will illuminate for approximately 2 seconds to indicate that the system is working.

When backing up at speed of less than 8 km/h (5 MPH), the system is constantly monitoring for object of interest located behind the vehicle. The rear parking assist system can detect objects greater than 7.6 cm (3 in) wide and 25.4 cm (10 in) tall. The system cannot detect objects below the bumper, underneath the vehicle,. If an object is detected, one of the following will occur:

* If the object is 1-2.5 m (3.3-8.2 ft) away from the vehicle, the amber outside indicator will illuminate and a single chime will sound when the object is first detected.
* If the object is 0.6-1.0 m (2-3.3 ft) away from the vehicle, the amber outside and the amber middle indicators will illuminate.
* If the object is 0.3-0.6 m (1-2 ft) away from the vehicle, the amber outside, amber middle, and red outside indicators will illuminate and the chime sounds continuously.
* If the object is less than 0.3 m (1 ft) away from the vehicle, the amber outside, amber middle, and red outside indicators will flash and the chime sounds continuously.

If the rear parking assist system detects a malfunction, a DTC will be stored and the parking assist control module will send a serial data message to the instrument panel cluster to display the SERVICE PARK ASSIST message on the driver information center. The red LED on the parking assist indicator will be illuminated as a notification to the driver that a malfunction exists and the system is disabled.

Rear Parking Assist System Driver Information Center Messages

SERVICE PARK ASSIST

The driver information center displays SERVICE PARK ASSIST when the parking assist control module detects a malfunction in the rear parking assist system and the system is disabled. The driver information center also displays SERVICE PARK ASSIST when a loss of communication occurs with the parking assist control module.

PARK ASSIST OFF

The PARK ASSIST OFF message is displayed in the driver information center when the parking assist system is disabled due to conditions that disable or inhibit the system. The red LED in the park assist indicator will be illuminated and the park assist switch indicator will be turned off. The parking assist control module requests the driver information center display PARK ASSIST OFF when it detects that one of the following conditions:

* The rear parking assist system is manually disabled by the vehicle operator through the parking assist switch or audio system personalization menu.
* An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, trailer hitch receiver, or tow bar. Also, an object extending beyond a lowered tailgate will disable the system.
* The parking assist sensors are covered by snow, mud, dirt, slush, or ice.
* The vehicle bumper is damaged.
* Excessive paint thickness on a replacement parking assist sensor.
* The parking assist sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.