Circuit Description

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The DTC P0300 Engine Misfire Detected diagnostic illuminates Malfunction Indicator Light (MIL) when a Not Cylinder Specific misfire is present. Powertrain Control Module (PCM) uses Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to determine engine misfire. CKP and CMP sensors monitor their respective components and evaluate changes in crankshaft rotational speed for each cylinder. Irregular changes in crankshaft rotational speed indicate a possible misfire. MIL illuminates when misfire rate equals or exceeds a pre-determined count. A misfire rate that is high enough can cause catalytic converter to overheat under certain driving conditions. MIL will flash ON and OFF when conditions for catalytic converter overheating are present. Each cylinder is monitored individually for a misfire condition. A DTC P0300 indicates engine misfire was indicated in more than one cylinder at the same time.