B2945

DTC B2945

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptor
DTC B2945
- Security System Sensor Power Circuit

Diagnostic Fault Information





Circuit/System Description

When the ignition is switched to the ON position, the body control module (BCM) supplies 12 volts to the theft deterrent exciter module. The BCM also provides a low reference for the exciter. With the voltage supplied to the exciter, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the BCM. The BCM then compares this value to a value stored in memory, learned key code. If the value received matches the stored value, the BCM sends the fuel enable password to the engine control module/powertrain control module (ECM/PCM) via serial data.

Conditions for Running the DTC

The ignition is OFF.

Conditions for Setting the DTC

The BCM detects a short to voltage on the security system sensor supply voltage circuit with the ignition OFF.

Action Taken When the DTC Sets

The DTC will set as current only with the ignition OFF. With the ignition ON, the DTC will always set as a history DTC.

Conditions for Clearing the DTC

* A current DTC will clear when the BCM no longer detects a circuit fault.
* A history DTC will clear after 100 fault-free ignition cycles.

Reference Information
Schematic Reference

Immobilizer Schematics (Immobilizer Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Immobilizer Description and Operation (Immobilizer Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the theft deterrent exciter.
2. Verify a test lamp does not illuminate between the B+ circuit terminal A and ground.

• If the test lamp illuminates, test the B+ circuit for a short to voltage. If the circuit tests normal, replace the BCM.

3. If all circuits test normal, test or replace the theft deterrent exciter.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for BCM replacement, setup, and programming