Scheme 1
Scheme 2
Circuit/System Description
Each object sensor is a 3-wire sensor that is both a transmitter and a receiver that includes a signal circuit, a low reference circuit, and an 8-volt supply voltage circuit. The object alarm module supplies 8 volts to the object sensors via the object sensor supply voltage circuit and provides ground via the low reference circuit. The object alarm module triggers the sensors in a sequential loop. After each sensor transmits, the object alarm module uses the echo or signal return to calculate the distance and position of an object from the rear bumper.
The object alarm module directly controls the rear parking assist (RPA) display. The RPA display consists of 2 amber and one red LED that indicate the distance of an object from the rear bumper. The object alarm module will also use an audible warning by sending a serial data message to the radio. Each object sensor is a 3-wire sensor that is both a transmitter and a receiver that includes a signal circuit, a low reference circuit, and an 8-volt supply voltage circuit. The object alarm module supplies 8 volts to the object sensors via the object sensor supply voltage circuit and provides ground via the low reference circuit. The object alarm module triggers the sensors in a sequential loop and after each sensor transmits, the object alarm module uses the echo or signal return to calculate the distance and position of an object from the rear bumper.
When the ignition is turned ON, the object alarm module performs a self-test to verify if any critical malfunction exists within the system. When the object alarm system has completed the power-up mode, the object alarm module establishes communication with the body control module (BCM). During the power-up mode the object detection module checks for a valid calibration data set, if no valid calibration set is found, the object alarm module disables the system and commands the red indicator ON.
When the ignition is turned ON, the object alarm module receives and stores the vehicle identification number (VIN) from the body control module (BCM). The BCM sends serial data messages to the object alarm module with the VIN information. The object alarm module will compare the VIN received to the VIN stored in memory. If the VIN stored in memory does not match the VIN transmitted by the BCM, the object alarm module sets a DTC and commands the red indicator ON indicating a system malfunction.
The object alarm detection system senses how close the vehicle is to an object. The distance is determined by the 4 ultrasonic sensors located in the rear and front (if equipped) bumpers. The object detection system will notify the driver when backing up while parking at speeds less than 8 km/h (5 mph). The object detection system will use front and rear display indicators and the radio speakers for notification.
The object alarm system will use the rear parking assist (RPA) display indicators and the radio speakers to notify the driver when an object is within the object alarm system field of view. Power is provided to the RPA display by the object alarm module via the RPA display supply voltage circuit. The RPA display indicators are controlled by the object alarm module via the indicator control circuits. The object alarm module provides the ground for the indicator control circuits. The object alarm module is grounded at G401.
The rear view camera image display module receives a 12-volt signal from the body control module (BCM) indicating that the vehicle is in reverse gear. When this signal is detected the rear view camera image display module will provide a regulated 6-volt power source to the rear view camera. The rear view image will then be displayed on the radio.
If a proper video signal is not detected, the radio will display a SERVICE REQUIRED notification on the radio display.
Object Alarm System Description
The object alarm module monitors the distance and how close a vehicle is to an object when backing up in a parking maneuver. The object alarm module will notify the driver of any objects of interest when backing up at speeds less than 8 km/h (5 mph). The distance between a vehicle and an object of interest is monitored by 4 ultrasonic sensors located in the rear bumper of the vehicle. The object alarm sensors receive the echo signal reflected off an object of interest while the vehicle is backing up at speeds less than 8 km/h (5 mph). The object alarm module receives the vehicle speed from the ECM via the serial data circuit. When the backing up speed exceeds 8 km/h (5 mph), the object alarm system is disabled. The object alarm system uses visual displays and audible warnings from the radio speakers to warn the driver of an object of interest within the defined field of view. The BCM controls the object alarm system chime function and sends serial data requests to the radio to sound the chime as needed. The visual display comprises of two amber and one red indicator and these indicators illuminate based on the vehicle distance to the object of interest. When the ignition is ON and the vehicle is placed into REVERSE, the object detection system performs a bulb check on the rear display.
Object Detection Alarm System Operation
The object detection system senses how close the vehicle is to an object. The distance is determined by the 4 ultrasonic sensors located in the rear bumper. When the system detects an object while the vehicle is in reverse, one of the following will occur
- If the object is less than 0.3 m (12 in) away from the vehicle, the amber outside, amber middle, and the red outside indicators flash and the chime sounds continuously for 5 seconds.
- If the object is less than 0.3-0.6 m (12-24 in) away from the vehicle, the amber outside, amber middle, and the red outside are ON.
- If the object is 0.6-1.0 m (24-40 in) away from the vehicle, the amber outside, and the amber middle indicators are ON.
- If the object is 1.0-2.5 m (40-98 in) away from the vehicle, the amber outside indicator is ON with a single chime and this is the first detection of an object.
The 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, the object detection system sends a serial data message to the instrument panel cluster (IPC) to display SERVICE PARK ASSIST on the driver information center (DIC). The chime will sound and the red indicator on the information center telltale assembly illuminates continuously, notifying the driver that a malfunction exist.
See also:
• Component Connector End Views