2010 Cadillac CTS Sedan AWD V6-3.6L Page 1540
DTC P0633 will set any time the ECM enters learn mode.
Action Taken When the DTC Sets
The security indicator will illuminate.
Conditions for Clearing the DTC
* A current DTC P0633 will be cleared upon a successful engine start after exit of learn mode.
* A history DTC will be cleared after 100 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
P0634
DTC P0634
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
