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

DTC P0300 sets when misfire which causes catalyst to overheat during 200 crankshaft revolutions is detected at 2 or more cylinders (MIL flashes as long as misfire occurs). When ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to TWC, but could cause exhaust emission deterioration. ECM will illuminate MIL when it detects malfunction during 2 consecutive drive cycles.

DTCs P0301, P0302, P0303 or P0304 sets when misfire which causes catalyst to overheat during 200 crankshaft revolutions is detected at any individual cylinder (MIL flashes as long as misfire occurs). When ECM detects a misfire (misfire rate per 1000 revolutions) which will not cause damage to TWC, but could cause exhaust emission deterioration. ECM will illuminate MIL when it detects malfunction during 2 consecutive drive cycles. Possible causes are:

• EGR system malfunction.
• Fuel injector malfunction.
• Fuel level sensor malfunction.
• Ignition system malfunction.
• Incorrect engine compression.
• Incorrect fuel pressure.
• Incorrect valve clearance.
• Incorrect valve timing.
• Intake system vacuum leaks.