Object Detection Description and Operation (UD7 with Display)

Object Detection Description and Operation (UD7 with Display)

The parking assist system is designed to identify and notify the driver of an object in the vehicle's path when reversing at speeds less than 8 km/h (5 mph). The distance and location of the object is determined by four object alarm sensors located in the rear bumper. The parking assist system will notify the driver using the rear parking assist display and an audible signal through the chime master.

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

* Rear object sensor control module
* Object alarm sensors
* Rear parking assist display

Rear Object Sensor Control Module

The rear object sensor control module provides an 8-volt reference and a low reference to the four object alarm sensors. The rear object sensor 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 rear object sensor control module will illuminate the appropriate LED on the rear parking assist display and send a serial data message requesting an audible alert.
Object Alarm Sensor

The object alarm sensors are located in the rear bumper of the vehicle. The sensors are used to determine the distance between an object and the rear bumper. Each sensor emits an ultrasonic frequency which is reflected off an 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, is used to determine the distance to the object. The sensors report this information to the rear object sensor control module.
Rear Parking Assist Display

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

Rear Parking Assist Operation

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

When backing up at speed 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 or underneath the vehicle. If an object is detected, one of the following will occur:

* If the object is 1-2.5 m (40-96 in) 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 (23-40 in) away from the vehicle, the amber outside and the amber middle indicators will illuminate.
* If the object is 0.3-0.6 m (11-23 in) 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 (12 in) away from the vehicle, the amber outside, amber middle, and red outside indicators will flash and the chime sounds continuously.

If the parking assist system detects a malfunction, a DTC will be stored and the rear object sensor control module will send a serial data message to the instrument panel cluster (IPC) to display the SERVICE PARK ASSIST message on the driver information center (DIC). A chime will sound and the red LED on the rear parking assist display will be illuminated, as a notification to the driver that a malfunction exists and the system is disabled.

Rear Parking Assist System DIC Messages
SERVICE PARK ASSIST

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

The PARK ASSIST OFF message is displayed in the DIC when the parking assist system is disabled due to conditions that disable or inhibit the system. The red LED in the rear parking assist display will be illuminated to indicate that the system has been disabled. The rear object sensor control module requests the DIC display PARK ASSIST OFF when it detects one of the following conditions:

* The parking assist system is manually disabled using the driver information center (DIC).
* The park brake is applied or not fully released.
* An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, trailer hitch receiver, or tow bar.
* The object alarm sensors are covered by snow, mud, dirt, slush, or ice.
* The vehicle bumper is damaged.
* Excessive paint thickness on a replacement object alarm sensor.
* The object alarm sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.