how to diagnose my Toyota Corolla E210 (2019-2024) with error code P0301?

Solution

1. Preparation

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

2. Replace Spark Plug

• Remove the Ignition Coil:
  • Unplug the ignition coil connector.
  • Remove the mounting bolts using a socket set.
• Replace Spark Plug:
  • Use a spark plug socket to remove the old spark plug.
  • Inspect the new spark plug for the correct gap (0.043 inches for most Toyota models).
  • Install the new spark plug by hand to avoid cross-threading, then torque to 13 lb-ft.
• Reinstall the Ignition Coil:
  • Secure the ignition coil back onto the spark plug and reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

• Remove Ignition Coil:
  • If the ignition coil for cylinder 1 is faulty, remove it as described above.
• Install New Ignition Coil:
  • Place the new ignition coil in position and secure it with the mounting bolts.
  • Reconnect the ignition coil connector.

4. Clean or Replace Fuel Injector (if necessary)

• Inspect Fuel Injector:
  • If the injector is clogged, clean it using a fuel injector cleaning kit or replace it if necessary.
• Reinstall the Fuel Injector:
  • If removed, reinstall it and ensure the electrical connector is properly attached.