Circuit/System Verification

WARNING: This page is about a different car, the 2011 Chevrolet Volt. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Because of normal system communications between the BCM and ECM, any immobilizer DTCs set in the BCM must be diagnosed prior to the diagnosis of immobilizer DTCs set in the ECM.
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.

Perform the ECM immobilizer learn using the Engine Control Module IMMO Learn function in SPS. 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.