how to fix P0301 misfire code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool and disconnect the battery to prevent electrical shock.
• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaning kit.

2. Inspect and Replace Spark Plug

• Remove the ignition coil for cylinder 1.
  • Use a socket wrench to remove the bolts securing the coil.
• Pull the ignition coil straight out of the spark plug hole.
• Remove the spark plug from cylinder 1 using a spark plug socket.
• Inspect the spark plug for wear (e.g., fouling, improper gap).
• If damaged, replace it with a new spark plug, ensuring the gap is set to manufacturer specifications (typically around 0.043 inches).
• Reinstall the ignition coil and secure it with bolts.

3. Test and Replace Ignition Coil

• Using a multimeter, check the resistance of the ignition coil.
  • Ensure it meets the specifications outlined in the service manual.
• If the coil is faulty, replace it with a new one.
• Reconnect the ignition coil and ensure a secure fit.

4. Clean or Replace Fuel Injector

• If the injector shows signs of blockage or poor function, consider cleaning it with a fuel injector cleaning kit.
• If cleaning does not resolve the issue, replace the fuel injector for cylinder 1.
  • Disconnect the fuel line and electrical connector from the injector.
  • Remove the old injector and install the new one, ensuring proper seating.
  • Reconnect the fuel line and electrical connector.

5. Compression Test

• Perform a compression test on cylinder 1.
• If compression is below manufacturer specifications, further diagnostics may be needed to assess potential internal engine issues (e.g., valve problems, piston rings).

6. Reassemble and Reconnect Battery

• Reinstall any components that were removed during the process.
• Reconnect the battery and ensure all connections are tight.