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.

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 .
Perform the 10-Minute 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, an undiagnosed no-start condition exists. Refer to the appropriate subsection and diagnostic to correct the no-start condition.