Supersedes Technical Service Bulletin Group 01 number 13-12 dated July 2, 2013. MIL on. DTC P1923 (Check DTC memory of Engine Control Module (ECM) 2) is stored in the engine control module J623 (address word 01). DTCs for random cylinder misfires (DTC P0300 - DTC P0308) are stored in the engine control module J624 (address word 11). This TSB has been proactively released to prevent the cylinder misfires from occurring on the vehicle.