GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

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

DTC Descriptors

DTC B1E3A 03: Sensor Power Circuit Voltage Below Threshold

DTC B1E3A 07: Sensor Power Circuit Voltage Above Threshold

Circuit/System Description

The object detection system senses how close the vehicle is to an object. The distance is determined by the 4 ultrasonic sensors located in the rear and front (if equipped) bumpers. The object detection system notifies the driver when backing up or moving forward while parking at speeds less than 8 km/h (5 mph). The object detection system makes parking easier and help avoid colliding with objects such as parked vehicles. The object detection system uses front and rear display indicators and the radio speakers for notification.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B1E3A 03

The object alarm module has detected the object alarm sensor supply voltage circuit is below 7.2 volts.

B1E3A 07

The object alarm module has detected the object alarm sensor supply voltage circuit is above 9.2 volts.

Action Taken When the DTC Sets

    • The object alarm module commands ON the information center telltale red indicator.
    • The object alarm module sends a serial data message to the instrument panel cluster (IPC) to display SERVICE PARK ASSIST message on the DIC, and the chime is commanded ON.

Conditions for Clearing the DTC

    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction-free warm-up cycles.

Reference Information

Schematic Reference

Object Detection Schematics

Connector End View Reference

Object Detection Connector End Views

Electrical Information Reference

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

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connectors at all rear object sensors.
  2. Important: A short to voltage on the component signal circuit may cause this DTC to set.

  3. Ignition ON, transmission in DRIVE for front parking assist and in REVERSE for rear parking assist, test for 8.0-9.0V between object sensor supply voltage circuit terminal 1 and ground.
  4. If less than the specified range, test the supply voltage circuit for a short to ground. If all circuits test normal, replace the object alarm module.
    If greater than the specified range, test the supply voltage circuit for a short to voltage. If all circuits test normal, replace the object alarm module.
  5. Connect each object sensor one at a time, while monitoring Sensor Feed Voltage Output scan tool parameter. The parameter value should be greater than 8.0V.
  6. If less than the specified value after an individual object sensor is connected, test or replace that object sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Object Sensor Replacement
    •  Front Object Alarm Sensor Replacement
    •  Control Module References for front and rear object alarm module replacement, setup, and programming.