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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery's negative terminal before starting work.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the electrical connector from the ignition coil of cylinder 1.
  3. Remove the ignition coil using a socket wrench.
  4. Unscrew the spark plug from cylinder 1 using a spark plug socket.
  5. Install a new spark plug, ensuring the correct gap (0.043 inches for most Toyota applications).
  6. Reinstall the ignition coil and connect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to measure the resistance of the ignition coil (refer to specifications in the service manual).
  2. If the coil is out of specification, replace it with a new one.
  3. Follow the same steps as above to remove and install the ignition coil.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Remove the fuel rail if necessary to access the injector.
  3. Inspect the fuel injector for clogs or physical damage.
  4. Clean the injector using an appropriate fuel injector cleaner or replace it if it cannot be cleaned.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine and observe the compression reading; it should be within manufacturer specifications (usually 180-200 psi).
  4. If the compression is low, further diagnosis for mechanical issues may be required.