Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0633: Immobilizer Key Not ProgrammedCircuit/System Description
When learning the security code, as well as the challenge and response sequence, the engine control module (ECM) is placed in learn mode. DTC P0633 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the security code and challenge/response are learned, learn mode will be exited when the engine is successfully started. If the ECM does not exit learn mode, P0633 will remain current and indicate a fault.
Conditions for Running the DTC
The ECM is in learn mode.
Conditions for Setting the DTC
DTC P0633 will set any time the ECM enters learn mode.
Action Taken When the DTC Sets
The security indicator in the instrument cluster 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
Connector End View Reference
Description and Operation
Immobilizer Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Note: Because of normal system communications between the body control module BCM and ECM, any immobilizer B-codes must be diagnosed prior to the diagnosis of P-codes. Refer to Diagnostic Trouble Code (DTC) List - Vehicle
Perform the Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming. 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 K20 Engine Control Module (ECM). |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming
