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

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is off and cooled down.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 1 by unbolting it and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for wear or damage; replace it if necessary.
• Install the new spark plug by hand, then torque it to the manufacturer’s specification (typically around 13 lb-ft for Toyota).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil (if necessary)

• If the spark plug appears fine, test the ignition coil for proper operation using a multimeter.
• If faulty, remove the ignition coil and replace it with a new unit.
• Reconnect all connectors and ensure it is securely fastened.

4. Inspect Fuel Injector

• Remove the fuel injector connector for cylinder 1.
• Use a multimeter to check for proper voltage at the connector.
• If there’s no signal, trace the wiring back to the ECU and repair as necessary.
• If the injector is clogged, remove it and clean using an ultrasonic cleaner or replace with a new injector.

5. Perform Compression Test

• Remove the spark plug from cylinder 1 and insert the compression tester.
• Crank the engine and record the compression readings.
• Compare the readings to specifications; if low, inspect for issues like valve sealing or head gasket failure.