Collision Avoidance and Parking Assist Systems: Description and Operation

Object Detection Description and Operation

Ultrasonic Rear Park Assist Operation

The ultrasonic rear park assist system senses how close the vehicle is to an object. The distance is determined by the 4 object sensors located in the rear bumper. The object detection system will notify the driver when backing up at speeds less than 8 km/h (5 mph). The object detection system will use the rear parking assist (RPA) display and the radio speakers for notification.

When the ignition is ON and the vehicle is placed into reverse, the object detection system performs a bulb check. During the bulb check, the 3 indicators on the RPA will illuminate for approximately 2 seconds to indicate that the system is working. The object detection system performs a bulb check and operates when the following conditions are present:

* The ignition is ON.
* The vehicle is placed in REVERSE (R) for rear parking aid.
* The vehicle speed is less than 5 km/h (3 mph). At speeds greater than 5 km/h (3 mph), the object detection system is disabled. The red indicator flashes to warn the driver that the object detection system is disabled.

The object detection system senses how close the vehicle is to an object. The distance is determined by the 4 object sensors located on the rear bumper. When the system detects an object, one of the following will occur:

* If the object is less than 0.3 m (11 in) away from the vehicle, the amber outside, amber middle, and the red outside indicators flash and the chime sounds continuously.
* If the object is less than 0.3-0.5 m (11-20 in) away from the vehicle, the amber outside, amber middle, and the red outside indicators are ON.
* If the object is 0.5-1.0 m (20-40 in) away from the vehicle, the amber outside, and the amber middle indicators are ON.
* If the object is 1-2.3 m (40-91 in) away from the vehicle, the amber outside indicator is ON.

Object detection system can detect objects 7.6 cm (3 in) wide and at least 25.4 cm (10 in) tall. It cannot detect objects above the level of the roof.

If the object detection system detects a malfunction, a diagnostic trouble code (DTC) will be stored and the object detection system will send a serial data communication message to the instrument panel (I/P) to SERVICE PARK ASSIST message on the driver information center (DIC). Then the chime will sound and the red indicator on the information telltale center will be lit continuously. The red LED in the rear display will be lit, notifying the driver that a malfunction exists. Message will clear once the driver acknowledges it.

Each object sensor is a three wire sensor that is both a transmitter and a receiver that comprises a signal circuit, a low reference circuit, and an 8-volt supply voltage circuit. The rear object control module supplies 8 volts to the object sensors via the object sensor supply voltage circuit and provides ground via the low reference circuit. The rear object control module triggers the sensors in a sequential loop and after each sensor transmits, the rear object control module uses the echo or signal return to calculate the distance and position of an object from the rear bumper. The rear object control module directly controls the RPA display.

Object Alarm 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 object detection system and sends a request to the DIC for display of the message. The DIC also displays SERVICE PARK ASSIST when there is a loss of communication 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 rear display, as well as, the telltale in the switch will be lit, notifying the driver the the PARK ASSIST system is disabled. The object alarm module requests the DIC via the serial data circuit to display PARK ASSIST OFF when it detects that one of the following conditions is true:

* Object alarm system disabled through DIC vehicle customization feature. Refer to the Owners Manual for more information.
* Automatic Object induced disable feature such as towing a trailer, bicycle rack, hitch receiver still attached to the vehicle.
* The park brake is not fully released.
* An object is hanging out of the endgate.
* The system receives vibrations from a large nearby vehicle or from a heavy equipment such as a jackhammer.

In the case of towing a trailer, the PARK ASSIST OFF message will continue to be displayed until the trailer hitch receiver is removed and the vehicle is driven forward above 24 km/h (15 mph).

Rear Vision Camera System Operation

The rear vision system can help a driver determine how close an object is to the rear bumper within a predefined rearward field of view. The system is composed of a video camera located on the rear liftgate, rear view camera image display module, electrical harness and the image display located on the radio.

The rear view camera image display module receives an active high (12-volt) signal from the body control module (BCM) when the vehicle is shifted into reverse. With the transmission is in the reverse, the rear view camera image display module will supply the camera with a regulated 6-volt power source. The rear view camera image display module also serves to process the video information from the camera and deliver it to the radio. The image from the rear view camera will only be displayed in the radio when the vehicle is in reverse.

The radio can display the following rear vision error messages:

* Rear Vision Camera System Unavailable-This message may display when the system is not receiving information it requires from other vehicle systems.
* Service Rear Vision Camera System-This message may display when the system is not receiving video from the camera.