The Engine Control Module (ECM) detects the following conditions:

•A timing calibration has been successfully completed.
•The primary engine speed/timing sensor and the secondary engine speed/timing sensor are off by more than three degrees.

Probable Causes:

1) Cluster gear is not properly aligned or it has damage
2) If cylinder head was removed, backlash for camshaft be out of spec
3) Engine speed sensors not installed properly