how to fix P0300 misfire code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery cable to prevent any electrical shorts.

2. Replace Spark Plugs

• Remove the engine cover if necessary using a socket set.
• Disconnect the ignition coil connectors from the spark plugs.
• Remove the ignition coils using a socket wrench and set them aside.
• Use a spark plug socket to remove the old spark plugs.
• Install new spark plugs, ensuring they are gapped correctly (typically 0.043 inches for the Corolla).
• Reinstall the ignition coils and reconnect the connectors.
• Replace the engine cover.

3. Inspect and Replace Ignition Coils (if necessary)

• If any ignition coils failed the multimeter test, remove the faulty coils as previously described.
• Install new ignition coils, ensuring proper alignment and sealing.
• Reconnect the ignition coil connectors.

4. Fuel System Check

• Attach a fuel pressure gauge to the fuel rail Schrader valve.
• Turn the ignition key to the "ON" position (do not start the engine) and record the fuel pressure reading.
• If the reading is below specifications (typically around 43-50 psi), consider replacing the fuel pump or checking the fuel filter for clogs.

5. Air Intake Inspection

• Inspect the air filter and replace it if dirty.
• Check the intake hoses for leaks or cracks and replace any damaged components.
• Ensure the mass air flow (MAF) sensor is clean; use MAF cleaner if necessary.