System Description

Misfire is monitored by evaluating fluctuations of the angular velocity of the crankshaft position sensor. The crankshaft position sensor allows the ECM to monitor crankshaft speed variations during each cylinder power stroke. When all cylinders of an engine are firing evenly, the crankshaft speeds up evenly with each power stroke. During a misfire, crankshaft speed decreases in that cylinder. kia OBD-II engines use a 60 minus 2 tooth crankshaft position sensor to measure crankshaft speed and position. The ECM uses this information to determine if a misfire occurs, which cylinder it is occurring in, and the degree of misfire. If a significant misfire is detected, a DTC is stored. The MIL in the instrument panel will illuminate, informing the driver of a malfunction.