how to fix P0301 misfire code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil on cylinder 1 by unbolting it and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for damage or excessive wear.
• If necessary, replace with a new spark plug, ensuring it matches the manufacturer's specifications.
• Torque the new spark plug to the recommended value (typically around 13-15 ft-lbs).

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil's resistance with a multimeter.
• If the resistance is out of specification, replace the ignition coil with a new one.
• Reinstall the ignition coil and connectors securely.

4. Inspect Fuel Injector

• Tools Required: Fuel injector cleaning kit or replacement injector set.
• If spark plug and ignition coil are functioning well, check the fuel injector for cylinder 1.
• Use a noid light to test the injector's electrical signal.
• If the injector is not firing, consider replacing it.
• If it is firing but clogged, clean it using a fuel injector cleaning kit.

5. Perform Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1 and connect the compression tester.
• Crank the engine and record the compression reading.
• Compare the reading with the manufacturer's specifications. If the compression is low, further engine diagnosis may be required.

6. Reassemble and Test

• Reassemble all components in reverse order.
• Reconnect the negative battery terminal.
• Start the engine and check for smooth operation.