Test Description

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

1. 3
   
   Inspect the following components:
   • The ignition system electrical wiring for correct electrical terminal connections or any pinches/cuts in the wires.
   • Clean and tight PCM grounds.
   • The proper connections of the vacuum hoses, as shown on the Vehicle Emission Information label.
   • Any air leaks at the intake manifold sealing surfaces.
2. 4
   
   This step determines if the DTC P0300 is the result of a hard malfunction or an intermittent condition.
3. 5
   
   If the misfire is not present, you may need to duplicate the conditions in the Freeze Frame data in order to detect the misfire. Depending on the engine load, the conditions may have to be maintained for up to 20 seconds. If the misfire accumulators start to increment, then this indicates that the misfire is present. A sudden change in the throttle, a rough road, or other crankshaft rotation disturbances may cause the counter to increment a few counts and then stop. This can be considered normal and should not be diagnosed as a misfire. The history counter begins counting after the DTC is set and will indicate only true misfires. A history misfire counter will store the number of misfires that have occurred until the DTC is cleared.
4. 11
   
   If a spark plug boot is burned, the other spark plug on that ignition coil may still fire at idle. This step tests the systems ability to produce at least 25,000 volts at each spark plug.
5. 14
   
   No spark on one coil may be caused by an open secondary circuit. Therefore, the coils secondary resistance should be tested. If resistance readings are more than 20,000 ohms, but are not infinite, this condition will probably not cause a no-start but may cause an engine miss during certain conditions.