Object Detection Description and Operation (Accessory Dealer Installed)

The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicles path when in reverse. The distance and location of the object is determined by 4 rear object sensors located in the rear bumper. The parking assist system will notify the driver using an audible beep from a dedicated object alarm module. The audible signal will vary depending on the distance the object is from the vehicle.

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

• Parking Assist Control Module
• Rear Object Alarm Sensors
• Object Alarm Module

Parking Assist Control Module 

The parking assist control module provides a reference voltage and a low reference to the four rear object sensors. The 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 module will command the object alarm module to provide an audible alert.

Rear Object Alarm Sensor 

The rear object 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 time, is used to determine the distance to the object. The sensors report this information to the parking assist control module.

Object Alarm Module 

The object alarm module is hardwired to the parking assist control module. The object alarm module is typically located behind a rear trim panel.

Rear Parking Assist Operation 

When the vehicle is running and first placed into reverse, an audible beep will sound to indicate the system is working. The parking assist control module receives its power from the reverse light circuit.

When backing up, the system is constantly monitoring for objects of interest located behind the vehicle. The 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 within 2.5 m (8 ft) away from the rear bumper, there will be an audible beep out of the object alarm module. As the vehicle gets closer to an object, the time between the beeps becomes shorter. If the vehicle stops moving and there is an object within 2.5 m (8 ft) away from the rear bumper the beeping will stop after 3 seconds. When the distance between the object and the vehicle starts to decrease again the beeping will start again.

If the parking assist system detects a malfunction when the vehicle is placed into reverse (vehicle running) the parking assist control module will immediately go into a diagnostic mode which provides a different frequency beep tone.