Theory Of Operation

The misfire detection monitor software strategy in the Powertrain Control Module (PCM) is designed to detect an engine misfire. The PCM uses the Crankshaft (CKP) and Camshaft (CMP) sensors to determine when an engine misfire event is occurring and determine individual misfire events by monitoring the crankshaft rotational speed. A misfire is nothing more than a lack of combustion, which can be caused by poor fuel quality or metering, low compression, or unmetered air entering the engine. On engines equipped with Exhaust Gas Recirculation (EGR), another possible cause is unwanted EGR flow. In the case of multiple cylinders misfiring or the PCM not determining the specific cylinder misfiring, P0300 Multiple Cylinder Misfire will set.