Object Detection Description and Operation Rear Parking Assist
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 signal through the radio.
The rear parking assist system is made up of the following components:
| • | Rear parking assist sensors |
| • | Parking assist indicator |
| • | Parking assist disable switch |
Object Alarm Module
The object alarm module provides an 8-volt reference and a low reference to the four rear parking assist sensors. The object alarm 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 object alarm 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 Parking Assist Sensor
The parking assist 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 ring time, is used to determine the distance to the object. The sensors report this information
to the object alarm 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 object alarm module controls these three LEDs as a visual indicator
of how close the vehicle bumper is to an object. The object alarm module supplies voltage to each of the LEDs and commands each LED on by supplying an individual ground.
Parking Assist Disable Switch
The parking assist disable switch is used as a means to manually disable the system, if desired. Pressing the switch will ground the park assist disable switch signal circuit, indicating to the object alarm module that a system disable is requested. The
object alarm module will respond by grounding the indicator control circuit, illuminating the indicator on the switch.
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 (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. |
| • | 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 rear parking assist system detects a malfunction, a DTC will be stored and the object alarm 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 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 DIC Messages
SERVICE PARK ASSIST
The driver information center (DIC) displays SERVICE PARK ASSIST when the object alarm module detects a malfunction in the rear parking assist system and the system is disabled. The DIC also displays SERVICE PARK ASSIST when a loss of communication occurs
with the object alarm module.
PARK ASSIST OFF
The PARK ASSIST OFF message is displayed in the DIC when the object alarm system is disabled due to conditions that disable or inhibit the system. The red LED in the park assist indicator will be illuminates, as will the disable indicator on the park assist
disable switch. The object alarm module requests the DIC display PARK ASSIST OFF when it detects that one of the following conditions:
| • | The rear parking assist system is manually disabled using the parking assist disable switch. |
| • | 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. 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. |
