Diagnostic Instructions

DTC Descriptors

DTC B0958 01: Parking Aid Rear Sensor 1 Left Corner Circuit Short to Battery

DTC B0958 06: Parking Aid Rear Sensor 1 Left Corner Circuit Short to Ground or Open

DTC B0958 08: Parking Aid Rear Sensor 1 Left Corner Circuit Signal Invalid

DTC B0958 21: Parking Aid Rear Sensor 1 Left Corner Circuit Incorrect Period

DTC B0959 01: Parking Aid Rear Sensor 1 Left Middle Circuit Short to Battery

DTC B0959 06: Parking Aid Rear Sensor 1 Left Middle Circuit Short to Ground or Open

DTC B0959 08: Parking Aid Rear Sensor 1 Left Middle Circuit Signal Invalid

DTC B0959 21: Parking Aid Rear Sensor 1 Left Middle Circuit Incorrect Period

DTC B0960 01: Parking Aid Rear Sensor 1 Right Middle Circuit Short to Battery

DTC B0960 06: Parking Aid Rear Sensor 1 Right Middle Circuit Short to Ground or Open

DTC B0960 08: Parking Aid Rear Sensor 1 Right Middle Circuit Signal Invalid

DTC B0960 21: Parking Aid Rear Sensor 1 Right Middle Circuit Incorrect Period

DTC B0961 01: Parking Aid Rear Sensor 1 Right Corner Circuit Short to Battery

DTC B0961 06: Parking Aid Rear Sensor 1 Right Corner Circuit Short to Ground or Open

DTC B0961 08: Parking Aid Rear Sensor 1 Right Corner Circuit Signal Invalid

DTC B0961 21: Parking Aid Rear Sensor 1 Right Corner Circuit Incorrect Period

Circuit/System Description

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.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0958 01, B0959 01, B0960 01, or B0961 01

The object sensor signal circuit output is greater than 11.5 volts.

B0958 06, B0959 06, B0960 06, or B0961 06

The object sensor signal circuit output is less than 0.5 volts.

B0958 08, B0959 08, B0960 08, or B0961 08

The object sensor signal circuit is invalid.

B0958 21, B0959 21, B0960 21, or B0961 21

The object sensor senses no change in an objects position when the vehicle is moving.

Action Taken When the DTC Sets

Reference Information

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

Circuit/System Verification

1. Verify that DTC B1E3A is not current.

⇒	If B1E3A is current, refer to DTC B1E3A .

2. Park brake disabled, transmission in REVERSE, suitable object behind an appropriate sensor, verify that the appropriate Rear Region scan tool parameter displays a value between Zone 1 and Zone 8.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the appropriate rear object sensor.
2. Ignition OFF for 30 seconds, test for less than 5.0 ohms between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the object alarm module.

3. Ignition ON, transmission in REVERSE, test for 8.0-9.0 volts between the rear object sensor supply voltage circuit terminal 1 and ground.

⇒	If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the object alarm module.

⇒	If less than the specified range, test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the object alarm module.

4. Ignition OFF, connect the appropriate rear object sensor and disconnect X1 harness connector at the object alarm module.
5. Ignition ON, test for less than 1.0V between signal circuit and ground of the appropriate rear object sensor listed below:

•	Left Rear middle object sensor signal circuit terminal 3

•	Left Rear corner object sensor signal circuit terminal 5

•	Right Rear middle object sensor signal circuit terminal 2

•	Right Rear corner object sensor signal circuit terminal 1

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

6. Ignition OFF, test for infinite resistance between signal circuit and ground of the appropriate rear object sensor listed below:

•	Left Rear middle object sensor signal circuit terminal 3

•	Left Rear corner object sensor signal circuit terminal 5

•	Right Rear middle object sensor signal circuit terminal 2

•	Right Rear corner object sensor signal circuit terminal 1

⇒	If less than the specified value, test the signal circuit for a short to ground.

7. Test for less than 2 ohms between the sensor signal circuit terminal 3 and signal circuit of the appropriate rear object sensor listed below:

•	Left Rear middle object sensor signal circuit terminal 3

•	Left Right corner object sensor signal circuit terminal 5

•	Right Rear middle object sensor signal circuit terminal 2

•	Right Rear corner object sensor signal circuit terminal 1

⇒	If greater than the specified range, test the signal circuit for an open/high resistance.

Important: Because the object alarm module does not update rear object sensor data when a DTC is set, the diagnostic can not determine whether the module or the sensor is causing the DTC to set.

8. If all circuits test normal, test or replace the appropriate rear object alarm sensor and verify that the DTC does not reset.

⇒	If the DTC resets, replace object alarm module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.