DTC P0300, P0301, P0302, P0303 Or P0304: Description

ECM monitors crankshaft revolution speed and engine speed via the Crankshaft Position (CKP) sensor and cylinder via the Camshaft Position (CMP) sensor. ECM detects occurrence of misfire by calculating changes in crankshaft revolution speed, and tracking how many times change occurred every 200 or 1000 engine revolutions. When ECM detects a misfire (misfire rate per 200 revolutions) which can cause overheating and damage to Three-Way Catalytic Converter (TWC), ECM causes MIL to flash for as long as misfire occurs. When misfire rate drops MIL remains illuminated until ECM detects normal driving conditions during 3 drive cycles. When ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to TWC, but could cause exhaust emission deterioration. ECM illuminates MIL after 2 drive cycles.