Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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