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

Solution

1. Preparation

• Gather tools and parts.
• Park the vehicle on a flat surface and engage the parking brake.
• Disconnect the negative battery terminal to avoid electrical shorts.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder one:
  • Unplug the electrical connector.
  • Remove the mounting bolts using a socket set.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install a new spark plug (gap to manufacturer's specification).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil

• If misfire persists after spark plug replacement, test the ignition coil:
  • Swap the ignition coil with another cylinder (e.g., cylinder two).
  • Clear the error codes and run the engine to see if the misfire follows the coil.
• If the misfire moves to the new cylinder, replace the faulty ignition coil.

4. Inspect Fuel Injector

• If the ignition coil is functional, check the fuel injector for cylinder one:
  • Disconnect the fuel injector connector.
  • Use a multimeter to test the injector resistance (should be within specified range).
• If faulty, replace the fuel injector.

5. Check for Vacuum Leaks

• Inspect hoses and gaskets around the intake manifold and throttle body for leaks.
• Use a smoke machine or carburetor cleaner to identify any leaks.
• Repair or replace any damaged components.

6. Verify Engine Compression

• Perform a compression test on cylinder one:
  • Remove the spark plug and connect a compression gauge.
  • Crank the engine and record the pressure.
• If compression is below specification, further engine diagnostics may be needed.