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.
DTCs P0300-P0306 Detection Logic
On DTCs P0300-P0306, MIL is set in 2 stages. If ECM detects misfiring strong enough to cause catalytic converter overheating for 200 consecutive engine revolutions, MIL will blink, but will not stay illuminated. If the ECM detects misfiring strong enough to cause deterioration of catalytic converter during 2 consecutive drive cycles for 1000 consecutive engine revolutions, MIL will illuminate.
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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.