Diagnostic Aids

If DTC P0300 is also set, start engine and allow it to idle. Using scan tool, read and record FREEZE FRAME data. Operate vehicle within conditions noted in FREEZE FRAME data. Using scan tool, read MISFIRE CUR # display for each cylinder. An increasing MISFIRE CUR # (indicating a misfire currently occurring) for any cylinder indicates location of faulty circuit or injector.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool display while moving all related harness and connectors. A change in scan tool display indicates fault location.