B2955
DTC B2955
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC B2955
- Security Sensor Data Circuit Malfunction
Diagnostic Fault Information
Circuit/System Description
When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coils surrounding the ignition lock cylinder. The transponder transmits a signal to the body control module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the engine control module (ECM). If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.
Conditions for Running the DTC
Ignition is in the Accessory or Run position.
Conditions for Setting the DTC
The BCM is unable to measure the ignition key transponder value.
Action Taken When the DTC Sets
* Vehicle starting will be disabled.
* The security indicator in the instrument cluster will be illuminated. A service message will be displayed in the driver information center.
Conditions for Clearing the DTC
* A current DTC will be cleared when the BCM detects a valid transponder value from the ignition key.
* A history DTC will be cleared after 100 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.
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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Inspect all available vehicle keys that they are correct vehicle keys.
• If not a correct vehicle key, replace the key.
2. Ignition OFF, disconnect the harness connector at the K64 Content Theft Deterrent Control Module and disconnect the harness connector X3 at the K9 Body Control Module, test for infinitive resistance between the signal circuit listed below and ground.
* K9 Body Control Module terminal 1 X3
* K9 Body Control Module terminal 2 X3
* K9 Body Control Module terminal 3 X3
• If less than the specified range, test the appropriate signal circuit for a short to ground.
3. Test for less than 0.3 V between the signal circuit listed below and ground:
* K9 Body Control Module terminal 1 X3
* K9 Body Control Module terminal 2 X3
* K9 Body Control Module terminal 3 X3
• If greater than the specified range, test the appropriate signal circuit for a short to voltage.
4. Test for less than 5 ohm between the signal circuit terminal listed below at the K9 Body Control Module and the signal circuit terminal listed below at the K64 Content Theft Deterrent Control Module.
* K9 Body Control Module terminal 1 X3 and K64 Content Theft Deterrent Control Module terminal 1
* K9 Body Control Module terminal 2 X3 and K64 Content Theft Deterrent Control Module terminal 2
* K9 Body Control Module terminal 3 X3 and K64 Content Theft Deterrent Control Module terminal 3
• If greater than the specified range, test the appropriate signal circuit for an open/high resistance.
5. If all circuits test normal, replace the K64 Content Theft Deterrent Control Module and verify that the customer concern is not still present.
• If the customer concern is still present, replace the K9 Body Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Replacing Keys (Erases All Existing Keys) (Replacing Keys (Erases All Existing Keys))
* Control Module References (Programming and Relearning) for control module replacement, setup and programming