how to fix P0301 misfire code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1 by unscrewing the retaining bolt and disconnecting the electrical connector.
• Use a spark plug socket to remove the old spark plug.
• Inspect the new spark plug for the correct gap (0.043 inches for Toyota Corolla) and install it.
• Reinstall the ignition coil over the new spark plug, reconnect the electrical connector, and secure it with the bolt.

3. Inspect and Possibly Replace Ignition Coil

• If the ignition coil appears damaged or testing indicates failure, replace it.
• Remove the ignition coil as described in Step 2.
• Install the new ignition coil by reversing the removal process.

4. Clean or Replace Fuel Injector

• Disconnect the fuel injector connector and remove the injector from the rail.
• Clean the injector with a suitable cleaner, or replace it if it is clogged or malfunctioning.
• Reinstall the injector, ensuring it is seated properly, and reconnect the electrical connector.

5. Perform Compression Test (if necessary)

• If previous steps did not resolve the issue, perform a compression test.
• Remove the spark plugs and use a compression gauge on cylinder 1.
• If the compression is below specifications (around 180 psi), further engine diagnostics may be required.

6. Final Steps

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.