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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and turned off.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil on cylinder 1 by unscrewing the retaining bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket.
• Inspect the old spark plug for wear and replace it with a new one, ensuring it is gapped as per the manufacturer's specifications (typically around 0.043 inches for the Corolla).
• Reinstall the ignition coil, securing it with the bolts and reconnecting the electrical connector.

3. Check and Replace Ignition Coil (if necessary)

• Tools Required: Socket set.
• If the ignition coil appears damaged during inspection, remove the coil as described above.
• Install a new ignition coil for cylinder 1, ensuring proper alignment and securing it with the bolts.
• Reconnect the electrical connector.

4. Inspect and Clean Fuel Injector (if necessary)

• Tools Required: Fuel injector cleaning kit (optional).
• Remove the fuel injector for cylinder 1 by disconnecting the injector plug and unscrewing the retaining bolts.
• Inspect the injector for clogs; clean it using a fuel injector cleaning kit if necessary.
• Reinstall the fuel injector, ensuring it is properly seated and secure.

5. Compression Test (if misfire persists)

• Tools Required: Compression gauge.
• Remove spark plugs from all cylinders for accurate testing.
• Insert the compression gauge into the cylinder 1 spark plug hole.
• Crank the engine a few times and record the compression reading; it should be within the manufacturer's specifications (typically 180-210 PSI).
• If compression is low, further diagnostics may be required for internal engine issues.