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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the ignition coil from cylinder 1 by unscrewing the bolts and disconnecting the electrical connector.
  2. Remove the spark plug using a spark plug socket and ratchet.
  3. Inspect the spark plug for wear or fouling. If necessary, replace it with a new spark plug (check the owner's manual for specifications).
  4. Torque the new spark plug to the manufacturer’s specifications (usually around 13 ft-lbs).
  5. Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the ignition coil appears faulty, remove it from cylinder 1.
  2. Install a new ignition coil, ensuring it aligns properly with the spark plug and is securely fastened.
  3. Reconnect the electrical connector to the ignition coil.

4. Test Fuel Injector (if necessary)

• Sub-steps:
  1. Remove the fuel injector connector from cylinder 1.
  2. Use a noid light to check if the injector is receiving a signal. If it does not light up, test the wiring and ECM.
  3. If the injector is faulty, remove it and replace it with a new one.
  4. Reconnect the injector electrical connector.

5. Compression Test (if necessary)

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression gauge into the spark plug hole and crank the engine for a few seconds.
  3. Compare the reading to the manufacturer's specifications. If low, further investigation is needed for potential internal engine issues.