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 bumper. The object detection system will notify the driver when backing up at speeds less than 8 km/h (5 mph), which make parking easier and helps you avoid colliding with objects such as parked vehicles.

Each object sensor is a 3-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 rear parking assist (RPA) display. The RPA consists of 2 amber and one red LED that indicate the range of an object from the rear bumper. The rear object control module will also use an audible warning by sending a low speed GMLAN message to the radio.

Ignition voltage is between 9-16 volts.

The following condition must exist for 300 milliseconds:

The object alarm module has detected that one of the three indicator control circuits for the rear display is determined to be open or shorted.

Schematic Reference

Object Detection Schematics

Connector End View Reference

Object Detection Connector End Views

Description and Operation

Object Detection Description and Operation

Electrical Information Reference

The red indicator displays continuously in the rear or front telltale assembly information center. If red indicator is not flashing, check if DTC is history.

1. Ignition OFF, disconnect the harness connector at the telltale assembly information center.
2. Ignition ON, place the transmission in reverse. Verify a test lamp illuminates when connected between the supply voltage circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the supply voltage circuit for a short to ground or an open/high resistance.

3. Ignition ON, scan tool installed, place the transmission in reverse. Verify that a test lamp illuminates when connected between the supply voltage circuit terminal A and each indicator control circuit terminals B, C, and D while performing the scan tool special functions LED test.

⇒	If the test lamp does not illuminate for one or more indicator control circuits, test the suspect indicator control circuit for a short to ground or an open/high resistance. If all the circuit(s) test normal, replace the telltale assembly information center.

4. If all circuits test normal, test or replace the object alarm module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for object alarm module replacement, setup, and programming