2010 Cadillac CTS Sedan AWD V6-3.0L Page 1470
The theft deterrent module (TDM) sends the prerelease password to the engine control module (ECM) via the serial data circuit. The ECM then
sends a challenge to the TDM. Both the ECM and TDM perform a calculation on this challenge. If the calculated response from the TDM equals
the calculation performed by the ECM, the ECM will allow vehicle starting.
Conditions for Running the DTC
Ignition is in the ACCESSORY or RUN position.
Conditions for Setting the DTC
The calculated response from the TDM does not equal the calculation performed by the ECM.
Action Taken When the DTC Sets
* The security indicator will illuminate.
* Vehicle starting will be disabled.
Conditions for Clearing the DTC
* A current DTC P0513 will be when a valid calculation is received.
* A history DTC will be cleared after 40 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.
Diagnostic Aids
The "key" referenced in the DTC descriptor does not refer to the vehicle key. In this case, "key" is referring to the challenge response.
Reference Information
Schematic Reference
Immobilizer Schematics (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Diagrams/Electrical Diagrams/Immobilizer
Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Immobilizer Description and Operation (without Y41) (See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Description and
Operation/Immobilizer Description and Operation (Without Y41))Immobilizer Description and Operation (with Y41) (See: Accessories and
Optional Equipment/Antitheft and Alarm Systems/Description and Operation/Immobilizer Description and Operation (With Y41))
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
Important: Because of normal system communications between the TDM and ECM, any theft deterrent B-codes must be diagnosed prior
to the diagnosis of P-codes.
Perform the 10-Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming (without RPO Y41) (See:
Accessories and Optional Equipment/Antitheft and Alarm Systems/Testing and Inspection/Programming and Relearning/Immobilizer System
Component Programming (without RPO Y41))Immobilizer System Component Programming (with RPO Y41) (See: Accessories and Optional
Equipment/Antitheft and Alarm Systems/Testing and Inspection/Programming and Relearning/Immobilizer System Component Programming (with
RPO Y41)). The ECM should successfully complete the password learn and the vehicle should start.
If the ECM does not complete the learn or vehicle starting remains disabled, replace the ECM.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
