how to fix P0301 misfire code in my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, and necessary replacement parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.

2. Replace Spark Plug

1. Disconnect the negative battery terminal.
2. Remove the engine cover (if applicable) using a socket set.
3. Locate and remove the spark plug wire or ignition coil for cylinder 1.
4. Use a spark plug socket to remove the spark plug.
5. Inspect the old spark plug for wear and gap; replace with a new spark plug if worn.
6. Install the new spark plug and torque to the manufacturer’s specifications (typically around 13 lb-ft).
7. Reconnect the ignition coil or spark plug wire.

3. Test and Replace Ignition Coil (if necessary)

1. Swap the ignition coil from cylinder 1 with another cylinder.
2. Reconnect the negative battery terminal and start the engine.
3. Monitor the OBD-II scanner for any new codes indicating misfires in the swapped cylinder.
4. If the misfire follows the ignition coil, replace it with a new one.

4. Inspect and Clean Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Test the injector using a multimeter to ensure it’s receiving power.
3. If it’s not functioning, replace the fuel injector.
4. If it’s functioning, clean the injector with a fuel injector cleaning solution.

5. Perform Compression Test

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for a few seconds and record the compression reading.
4. If compression is below specifications (usually around 180 psi), further investigation into engine internals is needed.