P0633
DTC P0633
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 P0633
- Theft Deterrent Key Not Programmed
Circuit/System Description
When learning the prerelease password, 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 password 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 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 Immobilizer Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
Immobilizer Description and Operation Immobilizer
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 Control Module References 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.
DTC P0633 will clear upon a successful engine start. Any malfunction that will cause a no-start condition will prevent DTC P0633 from clearing. Prior to diagnosing DTC P0633, ensure that all power moding and engine control systems are operating
properly and all conditions that may cause a no-start have been corrected. Do not replace the ECM. Replacing the ECM will not correct the no-start condition.
1. Ignition in the CRANK position, verify the scan tool Ignition Run/Crank parameter is Active.
• If not the specified value, refer to Power Mode Mismatch Power Mode Mismatch.
2. Perform the 10-Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming Programming and Relearning. 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, an undiagnosed no-start condition exists. Refer to the appropriate subsection and diagnostic to correct the no-start condition.