Test Description

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

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

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.

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.

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.

5

Steps 5 through 12 test for conditions that can cause a random cylinder misfire.

13

Steps 13 through 23 test for conditions that can cause a non-random or single cylinder misfire.