This Preliminary Information communication provides information to the technician on how to diagnose and repair vehicles with a no crank concern or they are unable to remove their key from the ignition lock cylinder may find Diagnostic Trouble Codes P0318, P1629, U1040, U1064, U1153, U1192, and U1300 stored in the Engine Control Module. Other Class 2 modules may have a U0100 and/or U1000 code stored. These concerns may be caused by an Ignition 1 Power Feed (circuit 5290) or Class 2 (circuit 1807) wiring concern to the Engine Control Module. If the electrical center ignition relay feedback parameter in the Engine Control Module is not battery voltage, measure the voltage at the Engine Control Module fuse in the under-hood fuse block. If voltage is less than battery voltage, check to make sure the Power Control Module is turning the relay on via circuit 5069. If there is battery voltage at the Engine Control Module fuse, check Ignition 1 (circuit 5290) between the fuse and the Engine Control Module. If Ignition 1 (circuit 5290) to the Engine Control Module checks ok, check for a possible open in the Class 2 (circuit 1807) to the Engine Control Module. If all connections and wiring are OK, suspect a possible relay or an ECM concern.
