Object Detection System - Park Assist System Buick LaCrosse II

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The object sensors are 3-wire sensors that are used to determine the distance between the vehicle and an object of interest. The parking assist control module supplies 8 V to the object sensors via the 8 V reference circuit and provides ground via the low reference circuit. The parking assist control module triggers the sensors in a sequential loop. After each sensor transmits, the parking assist control module uses the sensor echo received through the signal circuit to calculate the distance and position of an object.

Conditions for Running the DTC

1. Ignition ON
2. The parking assist is activated. The activation takes place through putting in the reverse gear or through operating the park assist switch.

Conditions for Setting the DTC

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

The parking assist control module has detected the voltage at the sensor circuit is greater than 11.5 V or the object sensor is not grounded.

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

The parking assist control module has detected the voltage at the sensor circuit less than 0.5 V.

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

The parking assist control module has received an invalid signal.

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

The object sensor determines no change in the position of an object while the vehicle is in motion.

B0958 3A, B0959 3A, B0960 3A, or B0961 3A

The parking assist control module determines the wrong sensor type is installed.

Action Taken When the DTC Sets

1. The parking assist is disabled.
2. The driver information center displays SERVICE PARK ASSIST.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify that DTC B1405 is not present. If DTC is present, refer to «DTC B1405»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) .
2. Verify that DTC B0958 01, B0959 01, B0960 01 or B0961 01 is not present. If DTC is present, check the appropriate sensor for contamination with mud, ice or snow. If no contamination is diagnosed, refer to Circuit/System Testing below.
3. Verify that DTC B0958 21, B0959 21, B0960 21 or B0961 21 is not present. If DTC is present, check the appropriate sensor for contamination with mud, ice or snow. If no contamination is diagnosed, replace the sensor.
4. Verify that DTC B0958 3A, B0959 3A, B0960 3A or B0961 3A is not present. If DTC is present, replace the appropriate sensor with a sensor of correct sensor type.
5. Ignition ON, transmission in REVERSE, verify the scan tool Parking Assist System Status parameter displays Enabled.

Circuit/System Testing

Note. Scan Tool must be disconnected for steps 1 and 2 to allow module to power down.

1. Ignition OFF for 1 min, disconnect the harness connector at the appropriate rear object sensor.
2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
3. Ignition ON, activate the parking assist, test for 7.5-9.0 V between the 8 V reference circuit terminal 1 and ground. If less than the specified range, test the 8 V reference circuit for an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
4. Activate the parking assist, test for 7.5-9.0 V between the signal circuit terminal 3 and ground. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
5. Replace the appropriate rear object sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Rear Parking Assist Alarm Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for parking assist control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The parking assist can be activated/deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

The indicator in the parking assist switch shows the status of the parking assist. If the lamp is ON, the parking assist is activated.

1. Ignition ON
2. The parking assist is activated. The activation takes place by putting in the reverse gear or by pressing the parking assist switch.

B0967 02

The parking assist control module has detected a short to ground.

B0968 01

The parking assist control module has detected a short to battery.

B0968 06

The parking assist control module has detected a short to ground or open.

1. The parking assist is disabled.
2. The driver information center displays SERVICE PARK ASSIST.

The condition for setting the DTC is no longer present.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC B0967 02 is not present. If DTC is present, refer to Parking Assist Switch Circuit Malfunction below.
2. Verify that B0968 01 or B0968 06 is not present. If DTC is present, refer to Parking Assist Switch Indicator Circuit Malfunction below.
3. Activate and deactivate the parking assist switch and verify the scan tool Park Assist Switch parameter changes between Active and Inactive.

Parking Assist Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
2. Test for less than 10 ohms between the ground circuit terminal 2 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
3. Connect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
4. Disconnect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module.
5. Ignition ON, test for less than 0.3 V between the signal circuit terminal 8 X1 and ground. If greater than the specified value, test the signal circuit for a short to voltage.
6. Ignition ON, verify that a test lamp does not illuminate between the B+ circuit terminal 1 X1 and signal circuit terminal 8 X1. If the test lamp illuminates, test signal circuit for a short to ground. If the circuit tests normal, replace the S48D Multifunction Switch 2 - Instrument Panel.
7. Verify that the test lamp illuminates between the B+ circuit terminal 1 X1 and signal circuit terminal 8 X1 while pressing the parking assist switch. If the test lamp does not illuminate, test the signal circuit for an open/high resistance. If all circuits test normal, replace the S48D Multifunction Switch 2 - Instrument Panel.
8. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.

Parking Assist Switch Indicator Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
2. Ignition ON, test for B+ between the ignition circuit terminal 3 and ground. If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance.
3. Command the Park Assist Switch LED output control ON with the scan tool. Test for B+ between the ignition circuit terminal 3 and the signal circuit terminal 6. If less than the specified value, test the signal circuit for an open/high resistance. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.
4. Command the Park Assist Switch LED output control OFF with the scan tool. Test for less than 0.3 V between the ignition circuit terminal 3 and the signal circuit terminal 6. If greater than the specified value, test the signal circuit for a short to ground. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.
5. If all circuits test normal, replace the S48D Multifunction Switch 2 - Instrument Panel.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Accessory Switch Replacement»(/buick/lacrosse/ii-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for parking assist control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When the ignition is turned ON, the parking assist control module and the side object sensors receive the vehicle identification number (VIN) from the body control module. The control modules will compare the VIN received to the VIN stored in memory.

Ignition voltage is between 9-16 V.

The stored VIN does not match the received VIN.

1. The parking assist or the side blind zone alert system is disabled.
2. The driver information center displays SERVICE PARK ASSIST or SERVICE SIDE BLIND ZONE ALERT SYSTEM.

The stored VIN matches the VIN stored in the body control module.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, verify the DTC B1015 is not set in either side object sensing module. If the DTC is set, refer to Side Object Sensing Module Malfunction below.
2. Verify the DTC B1015 is not set at the parking assist control module. If the DTC is set, refer to Parking Assist Control Module Malfunction below.

Side Object Sensing Module Malfunction

1. Ignition ON, with a scan tool, clear the DTCs.
2. Ignition OFF.
3. Wait 60 s, then ignition ON and verify the DTC is not reset. If the DTC is reset, replace the side object sensor the code set in.

Parking Assist Control Module Malfunction

1. Ignition ON, program the control module.
2. With a scan tool, clear the DTCs.
3. Ignition OFF.
4. Wait 60 s, then ignition ON and verify the DTC is not reset. If the DTC is reset, replace the K41 Front and Rear Parking Assist Control Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The object sensors are 3-wire sensors that are used to determine the distance between the vehicle and an object of interest. The parking assist control module supplies 8 V to the object sensors via the object sensor supply voltage circuit and provides ground via the object sensor low reference circuit. The parking assist control module triggers the sensors in a sequential loop. After each sensor transmits, the parking assist control module uses the sensor echo received through the object sensor signal circuit to calculate the distance and position of an object.

1. Ignition ON
2. Transmission in REVERSE

B1405 02

The parking assist control module has detected the object sensor supply voltage circuit is shorted to ground.

B1405 03

The parking assist control module has detected the object sensor supply voltage circuit is less than 7.2 V.

B1405 07

The parking assist control module has detected the object sensor supply voltage circuit is greater than 9.2 V.

1. The parking assist is disabled.
2. The driver information center displays SERVICE PARK ASSIST.

The condition for setting the DTC is no longer present.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, transmission in REVERSE, observe the scan tool Park Assist Sensor Reference Voltage parameter. The reading should be between 7.2-9.2 V.

1. Ignition OFF, disconnect the harness connector at each of the object sensors.
2. Ignition ON, transmission in REVERSE, test for 7.2-9.2 V between the object sensor supply voltage circuit terminal 1 at the B78G Rear Object Sensor - Left Outer harness connector and ground. If less than the specified range, test the object sensor supply voltage circuit for a short to ground. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module. If greater than the specified range, test the object sensor supply voltage circuit for a short to voltage. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
3. Install each object alarm sensor harness connector one at a time, checking DTCs after each sensor is connected. Verify DTC B1405 is not set as current. If the DTC is set, replace the object alarm sensor that was connected immediately before the DTC set.
4. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Rear Parking Assist Alarm Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for parking assist control module replacement, programming and setup

Symptoms - Object Detection

Note. The following steps must be completed before using the symptom tables

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Object Detection Description and Operation (UD7)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system__object-detection-description-and-operation-ud7) , «Object Detection Description and Operation (Accessory Dealer Installed)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system__object-detection-description-and-operation-accessory) , «Object Detection Description and Operation (UVC)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) , «Object Detection Description and Operation (UFT)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system__object-detection-description-and-operation-uft) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which may affect the operation of the system. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
3. Make sure the parking assist sensors located on the rear bumper are clear. Remove any snow, mud or ice that is blocking the sensors.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

1. «Parking Assist System Malfunction (Accessory Dealer Installed)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) , «Parking Assist System Malfunction (UD7)»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
2. «Rear Vision Camera System Malfunction»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
3. «Side Object Sensor Malfunction»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ultrasonic parking assist system is designed to identify and notify the driver of an object in the vehicles path when reversing at speeds of less than 8 km/h (5 MPH). The distance and location of the object is determined by four object sensors located in the rear bumper. The parking assist system will notify the driver using an audible signal through the radio.

Diagnostic Aids

The scan tool Park Assist Disable History parameters are a list of the seven previous reasons the parking assist system was disabled. These parameters may help in the diagnosis of an intermittent concern or a customer concern which is the result of normal system operation. The following is a brief description of potential causes which may aid in diagnosis

1. Manual Disable - The parking assist system has been disabled through the parking assist switch or audio system personalization menu.
2. Hitch/Object Attached - The parking assist control module is detecting an object that is attached to the vehicle. Common items such as a hitch receiver, trailer, or a bicycle rack may cause this concern. Additionally, damage to the rear of the vehicle or a misaligned sensor may cause this concern. If the vehicle is damaged in a manner that causes the sensor to detect the bumper itself, the parking assist control module will interpret this as an attached object and disable the system. Carefully inspect the bumper, bumper mounting surface, and sensor retainers before continuing with normal diagnosis. After the detected cause has been addressed the vehicle must be driven at speed greater than 40 km/h (25 MPH).
3. Reverse Overspeed - The vehicle is travelling too fast in reverse at speeds of greater than 8 km/h (5 MPH).
4. Inhibit - The parking assist control module has lost or received invalid GMLAN signal(s).
5. Sensor Disturbance - An outside interference is causing sensor movement. Such interference may be caused a heavy pounding, like that of a nearby jackhammer, or large changes in pressure, such as a large trucks air brakes.
6. Sensor Ring Time - If the sensor fails its own diagnostic initialization the parking assist control module will set this error. After the detected cause has been addressed the vehicle must be driven at speed greater than 40 km/h (25 MPH). The following is a list of reasons this cause may have set: One or more of the sensors may be blocked by snow, mud, ice, or other debris. This might happen after going through a car wash in cold weather. Silicone insulator surrounding sensor maybe missing, cut, or twisted. Improperly installed sensor, sensor maybe be crooked due to a tight wire harness. One or more of the sensors may be scratched or the paint maybe chipped. Excessive paint thickness on a sensor may cause an excessive sensor ring time. When replacing or refinishing a sensor, do not apply an excessive amount of paint or clear coat.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, verify the park assist system is enabled through the parking assist switch. If the park assist system is manually disabled, enable the system. Refer to the vehicle owners manual for instructions on enabling the system.
2. Observe the scan tool Park Assist Switch parameter while pressing and releasing the parking assist switch. The parameter should change between Active and Inactive. If the parameter does not change between the specified values, refer to Parking Assist Switch Circuit Malfunction below.
3. Command the Park Assist Switch LED ON and OFF with the scan tool. The parking assist switch indicator should turn ON and OFF when changing between the commanded states. If the indicator does not turn ON and OFF, refer to Parking Assist Switch Indicator Circuit Malfunction below.
4. Transmission in REVERSE, verify the scan tool Park Assist System Status parameter is Enable. If not the specified value, refer to Diagnostic Aids above and the scan tool Park Assist Disable History parameters to determine the cause of the inhibit.

Parking Assist Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
2. Test for less than 10 ohms between the ground circuit terminal 2 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
3. Connect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
4. Disconnect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module.
5. Ignition ON, test for less than 0.3 V between the signal circuit terminal 8 X1 and ground. If greater than the specified value, test the signal circuit for a short to voltage.
6. Ignition ON, verify that a test lamp does not illuminate between the B+ circuit terminal 1 X1 and signal circuit terminal 8 X1. If the test lamp illuminates, test signal circuit for a short to ground. If the circuit tests normal, replace the S48D Multifunction Switch 2 - Instrument Panel.
7. Verify that the test lamp illuminates between the B+ circuit terminal 1 X1 and signal circuit terminal 8 X1 while pressing the parking assist switch. If the test lamp does not illuminate, test the signal circuit for an open/high resistance. If all circuits test normal, replace the S48D Multifunction Switch 2 - Instrument Panel.
8. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.

Parking Assist Switch Indicator Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the S48D Multifunction Switch 2 - Instrument Panel.
2. Ignition ON, test for B+ between the ignition circuit terminal 3 and ground. If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
3. Command the Park Assist Switch LED output control ON with the scan tool. Test for B+ between the ignition circuit terminal 3 and the signal circuit terminal 6. If less than the specified value, test the signal circuit for an open/high resistance. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.
4. Command the Park Assist Switch LED output control OFF with the scan tool. Test for less than 0.3 V between the ignition circuit terminal 3 and the signal circuit terminal 6. If greater than the specified value, test the signal circuit for a short to ground. If all circuits test normal, replace the K41 Front and Rear Parking Assist Control Module.
5. If all circuits test normal, replace the S48D Multifunction Switch 2 - Instrument Panel.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Accessory Switch Replacement»(/buick/lacrosse/ii-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for parking assist control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ultrasonic parking assist system is designed to identify and notify the driver of an object in the vehicles path when reversing. The distance and location of the object is determined by four object sensors located in the rear bumper. The parking assist system will notify the driver using an audible signal through a dedicated alarm module. The parking assist system becomes active when the vehicle is put into reverse.

Parking Assist Sound Diagnostic Table

The vehicle needs to be running and in reverse for the parking assist system to work.

The frequency of the normal audible tone is 750 Mhz. If the rear parking assist system detects a system concern, the audible tone will change to 2 Khz (higher pitch).

The following is a brief description of potential causes which may aid in diagnosis

1. One or more of the sensors may be blocked by snow, mud, ice, or other debris. This might happen after going through a car wash in cold weather.
2. Silicone insulator surrounding sensor is missing, cut, or twisted.
3. Improperly installed sensor, sensor may be crooked due to a tight wire harness.
4. One or more of the sensors may be scratched or the paint is chipped.
5. Excessive paint thickness on a sensor may cause an excessive sensor ring time. When replacing or refinishing a sensor, do not apply an excessive amount of paint or clear coat.
6. An object is detected as being attached to the vehicle. Such as a hitch receiver, trailer, object hanging out of trunk, or bicycle rack.
7. Damage to the rear of the vehicle. Inspect the bumper, bumper mounting surfaces, and sensor retainers.
8. Outside frequency input to the sensor created by heavy pounding. Instances may be caused by a jackhammer or large changes in pressure, such as a large trucks air brakes.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Engine running, park brake on, transmission in reverse, verify that only one short beep (low pitch) sounds within 5 s to confirm that the object detection system is active.

1. If no audible tone is heard, refer to Object Alarm Module Circuit Malfunction below.
2. If a continuous (low pitch) tone is present, refer to Object Alarm Module Circuit Malfunction below.
3. If a continuous 5 s (high pitch) DTC tone is present, replace the K41 Front and Rear Parking Assist Control Module.
4. If one or more DTC beeps are present, check the appropriate rear object alarm sensor for contamination with mud, ice or snow. If no contamination is diagnosed, refer to Rear Object Alarm Sensor Circuit Malfunction below.

Object Alarm Module Circuit Malfunction

1. Engine running, park brake applied, transmission in reverse, verify that the reverse lights illuminate. If the reverse lamps do not illuminate, refer to «Backup Lamps Malfunction»(/buick/lacrosse/ii-2009-2013/remont/exterior-lights/#lighting-system-diagnostic-information-and-procedures) .
2. Ignition OFF, disconnect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module.
3. Test for less than 10 ohms between the ground circuit terminal 7 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
4. Vehicle in park, verify that a test lamp does not illuminate between the control circuit terminal 1 and ground. If the test lamp does illuminate, test the control circuit for short to voltage.
5. Engine running, park brake applied, transmission in reverse, verify that a test lamp illuminates between the control circuit terminal 1 and ground. If the test lamp does not illuminate, test the control circuit for short to ground or an open/high resistance. If all circuits test normal refer to «Backup Lamps Malfunction»(/buick/lacrosse/ii-2009-2013/remont/exterior-lights/#lighting-system-diagnostic-information-and-procedures) .
6. Ignition OFF, connect the X1 harness connector at the K41 Front and Rear Parking Assist Control Module.
7. Disconnect the harness connector at the P28 Speaker - Parking Assist.
8. Engine running, park brake applied, transmission in reverse, verify that a test lamp illuminates between the control circuit terminal 1 and ground. If the test lamp does not illuminate, test the control circuit for short to ground or an open/high resistance. If all circuits test normal, replace K41 Front and Rear Parking Assist Control Module.
9. Ignition OFF, connect test lamp between the control circuit terminal 1 and the control circuit terminal 2.
10. Engine running, park brake applied, while observing the test lamp, put the transmission in reverse. The test lamp should blink once as the transmission is put in reverse. If the test lamp is always on, test control circuit terminal 2 for short to ground. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module. If the test lamp is always off, test control circuit terminal 2 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
11. If all the circuits test normal, test or replace the P28 Speaker - Parking Assist.

Rear Object Alarm Sensor Circuit Malfunction

1. Ignition OFF for 30 s, disconnect the harness connector at the appropriate rear object alarm sensor.
2. Test for less than 10 ohms between the low reference circuit terminal 2 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
3. Engine running, park brake applied, transmission in reverse, test for 7.0-9. V between the 8 V reference circuit terminal 1 and ground. If less than 7.0 V, test the 8 V reference circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module. If greater than 9.0 V, test the 8 V reference circuit for a short to voltage. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
4. Ignition OFF, remove the malfunctioning rear object alarm sensor and swap locations with another properly functioning rear object alarm sensor. Connect the harness connector at both sensors.
5. Engine running, park brake applied, transmission in reverse verify the DTC tone is heard for the new location in which the malfunctioning sensor is installed. If the DTC tone is not heard for the new location, test the original location signal circuit terminal 3 for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the K41 Front and Rear Parking Assist Control Module.
6. If the DTC tone is heard for the new location in which the malfunctioning sensor is installed, replace the rear object alarm sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Note. For the dealer installed accessory parking assist system, the parking assist control module does not require any programming or setup.

1. «Rear Parking Assist Alarm Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
2. «Rear Object Alarm Control Module Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
3. Refer to «Rear Object Alarm Control Module Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) for Speaker - Parking Assist replacement.

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When the transmission is placed into REVERSE, a 12 V signal is sent to the rearview camera indicating that camera operation is requested. Ignition voltage and ground are supplied to the rearview camera. The rearview camera sends video information to the radio through a video signal + and a video signal - circuit. A grounded shielding also wraps the video signal circuits to reduce electronic interference which may degrade the video signal and cause a distorted or otherwise degraded image.

A poor video image can be caused by ice, snow, and mud buildup on the lens of the rearview camera. Also, extreme lighting conditions can affect performance, such as operating in the dark or with bright sunlight shining on the camera. Extreme high or low temperatures can also affect the image quality. An open in the shield of the video signal circuit can also cause a distorted screen.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC B2545 is not present. If DTC is present, refer to «DTC B2545»(/buick/lacrosse/ii-2009-2013/remont/exterior-lights/#lighting-system-diagnostic-information-and-procedures) .
2. Inspect the rearview camera and verify there are no debris on the lens and that the bezel or bezel seal is not damaged. If debris are found on the lens, clean the lens. If the lens, bezel, or bezel seal are damaged, replace as necessary.
3. Ignition ON, vehicle in PARK, verify the backup lamps are off. If the backup lamps are illuminated, refer to «Backup Lamps Malfunction»(/buick/lacrosse/ii-2009-2013/remont/exterior-lights/#lighting-system-diagnostic-information-and-procedures) .
4. Vehicle in REVERSE, verify the backup lamps are on. If the backup lamps are not illuminated, refer to «Backup Lamps Malfunction»(/buick/lacrosse/ii-2009-2013/remont/exterior-lights/#lighting-system-diagnostic-information-and-procedures) .
5. Engine running, transmission in REVERSE, verify a clear rear vision image is displayed on the radio. If a clear image is not displayed, refer to Circuit/System Testing below.

Note. Circuit/System Verification must be performed before Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the rearview camera.
2. Test for less than 5 ohms between the ground circuit terminal 5 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
3. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 6 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
4. Engine running, park brake applied, transmission in REVERSE, test for greater than 11 V between the control circuit terminal 3 and ground. If less than the specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
5. Ignition OFF, disconnect the X3 harness connector at the A11 Radio.
6. Ignition ON, test for less than 0.3 V between the following signal circuit terminals at the rearview camera harness connector and ground: Signal (+) circuit terminal 1 Signal (-) circuit terminal 4 If greater than the specified value, test the signal circuit for a short to voltage.
7. Test for infinite resistance between the following circuit terminals at the rearview camera harness connector and ground: Signal (+) circuit terminal 1 Signal (-) circuit terminal 4 If not the specified value, test the circuit for a short to ground.
8. Test for less than 5 ohms between the signal (+) circuit terminal 1 at the rearview camera harness connector and the signal (+) circuit terminal 5 X3 at the A11 Radio harness connector. If greater than the specified value, test the signal circuit for an open/high resistance.
9. Test for less than 5 ohms between the signal (-) circuit terminal 4 at the rearview camera harness connector and the signal (-) circuit terminal 15 X3 at the harness connector at A11 Radio. If greater than the specified value, test the signal circuit for an open/high resistance.
10. If all circuits test normal, replace the rearview camera.
11. Engine running, transmission in REVERSE, verify a clear rear vision image is displayed on the radio. If a clear rear vision image is not displayed, replace the A11 Radio.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Rearview Camera Image Display Module Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for body control module or radio replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The side blind zone alert system uses side object sensors located behind the rear fascia at each of the vehicles rear corners. Visual indicators located in the right and left outside rearview mirrors alert the driver to the presence of objects of interest within the corresponding blind spots, or zones, on each side of the vehicle. The system is controlled by the Vehicle Personalization settings located in the radio.

Each sensor receives battery power, ground, as well as serial data communications. The left and right sensors are identical, however an additional ground circuit is required to configure the sensor for operation on the right side. Communication is via a serial data and each sensor shares the serial data circuit in parallel, allowing continuation of communication between the sensors. The scan tool is able to communicate with each sensor independently. The side object sensors control corresponding mirror icons by sending power to the individual LED indicators.

1. The side object sensors are capable of detecting when they are blocked by mud, snow, or ice build up on the rear fascia. When a sensor is blocked, the driver information center will display SIDE BLIND ZONE SYSTEM UNAVAILABLE. The side blind zone alert system transitions back to the normal operating state when the blockage is removed. Bumper sticks, labels, and heavy rain storms may also cause this condition.
2. The side blind zone alert system is designed to ignore stationary objects; however, the system may occasionally detect guard rails, signs, trees, shrubs, or other stationary objects as an object in the blind zone. This is normal system operation and does not require service.
3. The side blind zone alert system may indicate an object in the blind zone if a trailer is attached to the vehicle, or a bicycle or object is extending out to either side of the vehicle.
4. The side blind zone alert system is disabled if any of the following occurs: There is a loss of serial data communication or a side blind zone alert system DTC is set. The side blind zone alert system is manually disabled by the driver through the radio.
5. Because the sensors are identical, they may be swapped from one side of the vehicle to the other in an attempt to isolate a concern. Sensors should NOT be swapped from one vehicle to another.

Schematic Reference

Object Detection Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Object Detection Description and Operation (UD7) , Object Detection Description and Operation (Accessory Dealer Installed) , Object Detection Description and Operation (UVC) , Object Detection Description and Operation (UFT)

Electrical Information Reference

1. «Circuit Testing»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, verify the scan tool can communicate with left side object sensor. If the scan tool can not communicate with the left side object sensor, refer to Left Side Object Sensor Malfunction below.
2. Verify the scan tool can communicate with right side object sensor. If the scan tool can not communicate with the right side object sensor, refer to Right Side Object Sensor Malfunction below.
3. Ignition ON, verify that the side blind zone alert system indicators located in the outside rearview mirrors briefly turn ON and then turn OFF during the system self test. If both indicators do not briefly illuminate during the system self test, the side blind zone alert system has been disabled. Refer to Diagnostic Aids above. If only one indicator does not briefly illuminate during the self test, refer to Side Object Indicator Malfunction below.

Left Side Object Sensor Malfunction

1. Ignition OFF, disconnect the harness connector at the B94L Side Object Sensor - Left.
2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 7 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the B94L Side Object Sensor - Left.

Right Side Object Sensor Malfunction

1. Ignition OFF, disconnect the harness connector at the B94R Side Object Sensor - Right.
2. Test for less than 5 ohms between the ground circuit terminals listed below and ground: Terminal 4 Terminal 3 If greater than the specified value, test the appropriate ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 7 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition OFF, disconnect the harness connector at the B94L Side Object Sensor - Left.
5. Ignition ON, test for less than 0.3 V between the serial data circuit terminal 5 and ground. If greater than the specified value, test the serial data circuit for a short to voltage.
6. Test for infinite resistance between the serial data circuit terminal 5 and ground. If not the specified value, test the serial data circuit for a short to ground.
7. Test for less than 5 ohms between the serial data circuit terminal 5 at the B94L Side Object Sensor - Left harness connector and the serial data circuit terminal 5 at the B94R Side Object Sensor - Right harness connector. If greater than the specified value, test the serial data circuit for an open/high resistance.
8. If all circuits test normal, replace the B94R Side Object Sensor - Right.

Side Object Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate outside rearview mirror.
2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 11 and the ground circuit terminal 4.
4. Ignition ON, verify the test lamp briefly illuminates during the system self test. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the appropriate side object sensor. If the test lamp remains illuminated at all time, test the control circuit for a short to voltage. If the circuits test normal, replace the appropriate side object sensor.
5. If all circuits test normal, replace the appropriate outside rearview mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Outside Rearview Mirror Replacement»(/buick/lacrosse/ii-2009-2013/remont/mirrors/#mirror-system)
2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for the driver door module, front passenger door module, side object sensor replacement, programming and setup

Scheme 5

Rear Object Alarm Control Module Replacement

Scheme 6

Side Object Sensor Replacement

Removal Procedure

1. Remove rear bumper fascia. Refer to «Rear Bumper Fascia Replacement»(/buick/lacrosse/ii-2009-2013/remont/exterior-body-panels/#bumpers-and-fascias) .
2. Disconnect electrical from the rear object sensor.
3. Lift the locking tabs on the housing and remove the rear object sensor.

Installation Procedure

1. Paint the rear object sensor. Refer to «Basecoat/Clearcoat Paint Systems»(/buick/lacrosse/ii-2009-2013/remont/paintcoatings/#paint-and-coatings__basecoatclearcoat-paint-systems) .
2. Ensure the paint does not exceed 6 mils. Use a paint thickness gauge suitable for non-ferrous metals. Refer to «Paint Gauges»(/buick/lacrosse/ii-2009-2013/remont/paintcoatings/#paint-and-coatings__paint-gauges) .
3. Insert the sensor into the housing.
4. Connect the electrical connector to the rear object sensor.
5. Install the rear bumper fascia. Refer to «Rear Bumper Fascia Replacement»(/buick/lacrosse/ii-2009-2013/remont/exterior-body-panels/#bumpers-and-fascias) .

The housings are adhesively retained to the backside of the fascia and must be removed prior to paint refinish operations every time the fascia is refinished due to paint bridging concerns. Adhesive tape cannot be removed and re-used with retention confidence. Thus the rear object sensor housing is considered a onetime use application, requiring that all 4 housings be replaced every time the fascia is refinished.

1. Remove the rear fascia. Refer to «Rear Bumper Fascia Replacement»(/buick/lacrosse/ii-2009-2013/remont/exterior-body-panels/#bumpers-and-fascias) .
2. Remove the rear object sensor. Refer to «Rear Parking Assist Alarm Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) .
3. Remove the sensor housing (1) from the fascia.
4. Remove all remaining adhesive.

1. Clean the sensor housing mating surface of the fascia with a lint-free rag using a naptha solvent or equivalent.
2. Mating surface must be dry before applying adhesion promoter.
3. Apply adhesion promoter 3M Products P/N 06396 or equivalent to the sensor housing mating surface (1) of the fascia.
4. Remove the protective paper backing from the sensor housing.
5. Position the sensor housing (1) to the fascia.
6. Press firmly to secure the sensor housing to the fascia.
7. Install the rear object sensor. Refer to «Rear Parking Assist Alarm Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/collisionavoidance/#object-detection-system-park-assist-system) .
8. Install the rear fascia. Refer to «Rear Bumper Fascia Replacement»(/buick/lacrosse/ii-2009-2013/remont/exterior-body-panels/#bumpers-and-fascias) .

Scheme 7

Rearview Camera Image Display Module Replacement

Rear Vision Camera System Operation

The components used in the rear vision camera system are the camera, located at the rear of the vehicle, and the navigation radio.

When the vehicle is placed in REVERSE, the body control module sends a 12 V signal to the rearview camera. This signal indicates that rear vision camera operation is required. Upon receipt of this signal, the camera will begin the power up cycle. A serial data message is also received by the navigation radio indicating the vehicle is in REVERSE. Upon receipt of this message, the navigation radio will also begin a power up cycle for the display. The rear vision camera transmits the video signal to the navigation radio through discrete + and - signal circuits. A metallic foil encases the video signal circuits and is tied to a shield ground circuit. This shield is designed to reduce electronic interference which may degrade the video signal and cause a distorted or otherwise degraded image.

If desired, the rear vision camera may be manually disabled through the navigation system menu. Refer to the navigation system owners manual for instructions on manually disabling and enabling the rear vision camera system. The following conditions may cause a degraded rear vision camera image

1. Ice, snow, or mud has built up on the rear vision camera
2. Dark conditions
3. Extreme light conditions, such as glare from the sun or the headlights of another vehicle
4. Damage to the rear of the vehicle
5. Extreme high or low temperatures or extreme temperature changes

If a malfunction is detected in the system, Service Rear Vision Camera may be displayed on the navigation radio as an indicator to the customer that a problem exists that requires service.

Object Detection Description and Operation (Accessory Dealer Installed)

The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicles path when in reverse. The distance and location of the object is determined by 4 rear object sensors located in the rear bumper. The parking assist system will notify the driver using an audible beep from a dedicated object alarm module. The audible signal will vary depending on the distance the object is from the vehicle.

The rear parking assist system is made up of the following components

1. Parking Assist Control Module
2. Rear Object Alarm Sensors
3. Object Alarm Module

Parking Assist Control Module

The parking assist control module provides a reference voltage and a low reference to the four rear object sensors. The 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 module will command the object alarm module to provide an audible alert.

Rear Object Alarm Sensor

The rear object sensors are located in the rear bumper of the vehicle. The sensors are used to determine the distance between an object and the rear bumper. Each sensor emits an ultrasonic frequency which is reflected off an 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 echo time, is used to determine the distance to the object. The sensors report this information to the parking assist control module.

Object Alarm Module

The object alarm module is hardwired to the parking assist control module. The object alarm module is typically located behind a rear trim panel.

Rear Parking Assist Operation

When the vehicle is running and first placed into reverse, an audible beep will sound to indicate the system is working. The parking assist control module receives its power from the reverse light circuit.

When backing up, the system is constantly monitoring for objects of interest located behind the vehicle. The 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 or underneath the vehicle. If an object is detected within 2.5 m (8 ft) away from the rear bumper, there will be an audible beep out of the object alarm module. As the vehicle gets closer to an object, the time between the beeps becomes shorter. If the vehicle stops moving and there is an object within 2.5 m (8 ft) away from the rear bumper the beeping will stop after 3 seconds. When the distance between the object and the vehicle starts to decrease again the beeping will start again.

If the parking assist system detects a malfunction when the vehicle is placed into reverse (vehicle running) the parking assist control module will immediately go into a diagnostic mode which provides a different frequency beep tone.

Object Detection Description and Operation (UD7)

The ultrasonic parking assist system is designed to identify and notify the driver of an object in the vehicles 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 an audible beep signal through the radio.

The parking assist system is made up of the following components

1. Parking assist control module
2. Rear object alarm sensors
3. Parking assist switch
4. Parking assist switch indicator

Parking Assist Control Module

The parking assist control module provides an 8 V reference and a low reference to the four object alarm sensors. The parking assist control 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 parking assist control module will send a data message via CAN-Bus to the radio requesting an audible alert.

Rear Object Alarm Sensors

The object alarm sensors are located in the rear bumper of the vehicle. The sensors are used to determine the distance between an object and the bumper. Each sensor emits an ultrasonic frequency which is reflected off any object located behind the vehicle. These reflections are received by the sensors. The time difference between the emission of the frequency and when the reflection is received is known as sensor echo time, it is used to determine the distance to the object. The sensors report this information to the parking assist control module.

Parking Assist Switch

The parking assist can be activated and deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

Parking Assist Switch Indicator

The indicator in the parking assist switch shows the status of the parking assist. If the lamp is ON, the parking assist is activated.

Rear Parking Assist Operation

When an object is within the measuring range of the sensor, the ultrasonic pulse is reflected and is received by the sending or a neighboring sensor. The sensor converts this signal into a voltage signal and sends this signal to the parking assist control module. The parking assist control module evaluates the received sensor signals. As soon as an object is within the measuring range, the parking assist control module sends a message to the radio in order to give out the acoustic distance signal. If an object is detected within 2.5 m (8 ft) away from the rear bumper, there will be an audible beep out of the speakers. As the vehicle gets closer to an object, the time between the beeps becomes shorter. If the vehicle stops and there is an object within 2.5 m (8 ft) away from the rear bumper the beeping will stop after 5 s. When the distance between the object and the vehicle starts to decrease again the beeping will start again. From a distance less than 30 cm (9.84 in), the sound becomes continuous.

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.

The parking assist can be activated and deactivated by pressing the parking assist switch. By engaging the reverse gear the parking assist can also be activated. By subsequently pressing the parking assist switch the parking assist can be disabled again.

The parking assist control module carries out a self test and monitors the sensors for electrical and mechanical faults. Monitored is the power supply of each sensor and the sensor signals, which need to alter when the vehicle moves. If this is not the case, the sensor is acoustically blocked or faulty. Mud, ice and snow may cause obstruction of the function of the sensors. Besides that the parking assist control module checks whether the correct type of sensor is installed. If any of these tests fails, a DTC with corresponding symptom is set, the parking assist is deactivated and the parking assist control module will send a serial data message to display the SERVICE PARK ASSIST message on the driver information center

Rear Parking Assist System Driver Information Center Messages

SERVICE PARK ASSIST

The driver information center displays SERVICE PARK ASSIST when the parking assist control module detects a malfunction in the rear parking assist system and the system is disabled. The driver information center also displays SERVICE PARK ASSIST when a loss of communication occurs with the parking assist control module.

PARK ASSIST OFF

The PARK ASSIST OFF message is displayed in the driver information center when the parking assist system is disabled due to conditions that disable or inhibit the system. The parking assist control module requests the driver information center display PARK ASSIST OFF when it detects that one of the following conditions

1. The rear parking assist system is manually disabled by the vehicle operator through the parking assist switch or audio system personalization menu.
2. 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 endgate will disable the system.
3. The parking assist sensors are covered by snow, mud, dirt, slush, or ice.
4. The vehicle bumper is damaged.
5. Excessive paint thickness on a replacement parking assist sensor.
6. The parking assist sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.

Object Detection Description and Operation (UFT)

The side blind zone alert system is designed to detect vehicles or other objects that may be located in the vehicles blind spots. This detection is performed by two side object sensors, located behind the rear fascia on each side of the vehicle. When an object is detected in a blind spot, an indicator in the outside rearview mirror will illuminate, notifying the driver that it is unsafe to change lanes.

The side blind zone alert system is made up of the following components

1. Left side object sensor
2. Right side object sensor
3. Driver outside rearview mirror
4. Passenger outside rearview mirror

Side Object Sensors

The side object sensors are each located behind the rear fascia, positioned so that the sensor is pointing out toward the opposite lane. Each sensor is supplied B+ and ground. The right sensor receives an additional ground. Both sensors communicate independently on the serial data line. The serial data enters the left sensor in a pass-thru configuration, that connects to the right sensor. The scan tool is able to individually communicate with each sensor.

When a vehicle or object is detected by a side object sensor, the sensor will illuminate the indicator located in the appropriate outside rearview mirror.

Outside Rearview Mirror

The outside rearview mirrors each contain an indicator that is controlled by the appropriate side object sensor. This indicator is illuminated when a vehicle or object is positioned in the vehicles blind spot.

Side Blind Zone Alert Operation

When the vehicle is started, the indicators located in the outside rearview mirror will briefly illuminate to indicate that the system is operating. The side object sensors cover a zone of approximately one lane over from both sides of the vehicle, 3.5 m (11 ft). This zone starts at each side mirror and goes back approximately 5.0 m (16 ft). The height of the zone is approximately between 0.5 m (1.5 ft) and 2.0 m (6 ft) off the ground. When a vehicle or object is detected in this area, the appropriate indicator will be illuminated, indicating to the driver that it is unsafe to change lanes. If a turn signal is activated while the indicator is illuminated, the indicator will flash as a more urgent warning that a lane change may be unsafe.

Foul weather may affect the operation of the side blind zone alert system. Occasional missed alerts can occur under normal circumstances and will increase in wet conditions. The number of missed alerts will increase with increased rainfall or road spray. Heavy rainfall, as well as mud, dirt, snow, ice, or slush build-up on the rear fascia, will completely disable the system.

If the vehicle is towing a trailer or has an object, such as a bicycle rack, attached to the rear of the vehicle, the side blind zone alert system may not function properly and the indicators will remain illuminated at all time.

Side Blind Zone Alert Driver Information Center Messages

SIDE BLIND ZONE ALERT SYSTEM OFF

This message indicates that the system has been disabled through the Vehicle Personalization located in the radio. Refer to the vehicle owners manual for instructions on how to set personalization options on the driver information center.

SIDE BLIND ZONE SYSTEM UNAVAILABLE

This message indicates that the system has been disabled because the sensor is blocked or can otherwise not accurately detect vehicles or objects. Such instances may be mud, dirt, snow, ice, or slush build-up on the rear fascia, heavy rainfall, or excessive road spray.

SERVICE SIDE BLIND ZONE ALERT SYSTEM

This message indicates that the system requires service. When the message is displayed, the indicators will remain illuminated at all times, notifying the driver that the side blind zone alert system should not be relied upon when changing lanes.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Accessory Switch Replacement
• Checking Aftermarket Accessories
• Backup Lamps Malfunction
• Outside Rearview Mirror Replacement
• Rear Compartment Side Trim Panel Replacement (without HP6)
• Rear Bumper Fascia Replacement
• Basecoat/Clearcoat Paint Systems
• Paint Gauges
• Rear Compartment Lid Applique Replacement
• DTC B0958, B0959, B0960, or B0961
• Object Detection Description and Operation (UD7)
• Object Detection Description and Operation (Accessory Dealer Installed)
• Object Detection Description and Operation (UFT)