GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Avalanche - 4WD 🢒 Safety and Security 🢒 Object Detection 🢒 Side Object Sensor Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The Side Blind Zone Alert (SBZA) system uses side object sensors located behind the fascia at each of the vehicle's 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 driver information center (DIC) which can also communicate its status.

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 messages to the door modules which in turn switch power to the LED indicators.

Diagnostic Aids
    • The side object sensors are capable of detecting when they are blocked by mud, snow, or ice build up on the fascia. When a sensor is blocked, the driver information center (DIC) will display SIDE BLIND ZONE SYSTEM UNAVAILABLE. The SBZA 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.
    • The SBZA 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.
    • The SBZA 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.
    • The SBZA system is disabled if any of the following occurs:
       - The door modules determine that a malfunction exists in the side object indicator.
       - There is a loss of serial data communication or a SBZA system DTC is set.
       - The SBZA system is manually disabled by the driver through the DIC.
    • Each side object sensor maintains a history buffer of the previous 16 SBZA events which can be accessed using the scan tool. These parameters may be used to help diagnose a system malfunction or an intermittent concern.
    • 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.

Reference Information

Schematic Reference

Object Detection Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Object Detection Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, verify the scan tool can communicate with right side object sensor.
    2. ⇒If the scan tool can not communicate with the right side object sensor, refer to Right Side Object Sensor Malfunction
  2. Verify the scan tool can communicate with left side object sensor.
    3. ⇒If the scan tool can not communicate with the left side object sensor, refer to Left Side Object Sensor Malfunction
  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.
    4. ⇒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.
    ⇒If only one indicator does not briefly illuminate during the self test, refer to Side Object Indicator Malfunction.

Circuit/System Testing

Right Side Object Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the right side object sensor.
  2. Test for less than 5 Ω between the ground circuit terminals listed below and ground:
    3. • Terminal 5
    • Terminal 6
    ⇒If greater than the specified range, test the appropriate ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    4. ⇒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 right side object sensor.

Left Side Object Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the left side object sensor.
  2. Test for less than 5 Ω between the ground circuit terminal 5 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
    4. ⇒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 right side object sensor.
  5. Ignition ON, test for less than 1 V between the serial data circuit terminal 4 and ground.
    6. ⇒If greater than the specified range, test the serial data circuit for a short to ground.
  6. Test for infinite resistance between the serial data circuit terminal 4 and ground.
    7. ⇒If not the specified value, test the serial data circuit for a short to ground.
  7. Test for less than 2 Ω between the serial data circuit terminal 4 at the left side object sensor harness connector and the serial data circuit terminal 4 at the right side object sensor harness connector.
    8. ⇒If greater than the specified range, test the serial data circuit for an open/high resistance.
  8. If all circuits test normal, replace the left side object sensor.

Side Object Indicator Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the outside rearview mirror.
  2. Connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 1.
  3. Ignition ON, verify the test lamp briefly illuminates during the system self test.
    4. ⇒If the test lamp does not illuminate or remains illuminated at all time, test the control circuit and the low reference circuit for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal, replace the appropriate door module.
  4. If all circuits test normal, test or replace the appropriate outside rearview mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Power Mirror Replacement
    •  Control Module References for the driver door module, front passenger door module, side object sensor replacement, setup, and programming