Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2
   
   A malfunctioning injector circuit, crankshaft position system variation not learned condition, or incorrect rough road data from the Electronic Brake Control Module (EBCM) may cause a misfire DTC to be set. If any of the indicated DTCs are set with DTC P0300, diagnose and repair the other DTC before using the DTC P0300 procedure.
2. 3
   
   The MISFIRE CURRENT CYL # display may normally display a small amount of activity (0-10 counts) but should not steadily increment during an entire 200 revolution test sample period.
3. 4
   
   Depending on the cause of the misfire, the MISFIRE HISTORY CYL # counter will display a very large number for the misfiring cylinders. Values for the non-misfiring cylinders will be less than 1/2 as great as the misfiring cylinders. When investigating a misfire, always start with items associated with the cylinders that have the largest number of counts stored in the MISFIRE HISTORY CYL # counter.
4. 5
   
   Steps 5 through 12 test for conditions that can cause a random cylinder misfire.
5. 13
   
   Steps 13 through 23 test for conditions that can cause a non-random or single cylinder misfire.