DTC P0300 Random/Multiple Cylinder Misfire Detected; DTC P0301 Cylinder 1 - Misfire Detected; DTC P0302 Cylinder 2 - Misfire Detected; DTC P0303 Cylinder 3 - Misfire Detected; DTC P0304 Cylinder 4 - Misfire Detected: General Description

Misfires can be caused by lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or many other causes. Even a small number of misfires may result in excessive exhaust emissions due to the unburned mixture. Increased misfire rates cause damage to the catalytic converter. The ECM/PCM monitors the crankshaft speed variation to determine if any misfiring generated. The ECM/PCM identifies the specific cylinder in which the misfire has occurred and counts individual misfire events by monitoring changes in the crankshaft rotation for each cylinder. A random misfire indicates two or more cylinders are misfiring.