Possible Causes
WARNING: This page is about a different car, the 2003 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For any particular 200 revolutions of engine, misfiring which could result in overheating of catalyst is detected. This will cause MIL to blink (1 trip detection logic).
NOTE:
For any particular 1000 revolutions of engine, misfiring which could result in a deterioration of emissions. This will cause MIL to light up (2 trip detection logic).
NOTE:
When 2 or more DTCs for misfiring cylinder are recorded repeatedly and DTC P0300 does not exist, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, the reason may be because vehicle was driven with a lack of fuel, improper fuel, fouled spark plug, etc.
DTC is set when misfiring cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are:
- Open or short in engine wiring harness.
- Defective connections at ECM or component.
- Disconnected, restricted or damaged vacuum hose(s).
- Ignition system malfunction.
- Defective fuel injector(s).
- Improper fuel pressure.
- Defective Mass Airflow (MAF) meter.
- Defective Engine Coolant Temperature (ECT) sensor.
- Improper engine compression.
- Improper valve clearance.
- Improper valve timing.
- Defective Positive Crankcase Ventilation (PCV) valve piping.
- Defective ECM.