P1649

DTC P1649

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 P1649
- Immobiliser Security Code Not Programmed




Circuit/System Description

Certain modules use a security code as a means of theft deterrence. Each vehicle is assigned a specific four-digit security code at the time of manufacturer. This security code is used by multiple modules which require a correct security code to operate properly. If a security code is not programming or an incorrect security code is programmed which does not match that of the vehicle, vehicle starting is disabled.


The following modules utilize security code:

* Engine control module (ECM)
* Steering column module (CIM)
* Instrument panel cluster (IPC)
* Underhood electrical center (UEC)
* Rear electrical center (REC)



Conditions for Running the DTC

Ignition ON


Conditions for Setting the DTC

No security code is programmed in the module


Action Taken When the DTC Sets

* Vehicle starting is disabled
* The Service Vehicle Soon indicator will flash



Conditions for Clearing the DTC

* A current DTC will be cleared when a security code is programmed to the module.
* A history DTC will clear after 100 malfunction 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 Verification


Important: When reprogramming a control module which has already been programmed, additional security measures must be met before reprogramming is allowed. Prior to programming, security access must be granted by connecting a Tech 2 in a pass-thru arraignment and requesting security access in TIS. Once security access is granted, the security code must be entered. The security code can be found in DealerWorld. Both of these security measures must be met before the Reset ECU selection is allowed.


1. Ignition ON, select Reset ECU on the scan tool for the ECM.
2. Perform the Programming and Setup procedure for the ECM. Refer to Control Module References (Programming and Relearning) for programming and setup procedures. Verify the DTC does not reset after programming.

• If the DTC resets, replace the ECM.




Repair Instructions

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


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