why does my Toyota Corolla E210 (2019-2024) have a check engine light with code P0301

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Locate the spark plug for cylinder 1.
  3. Use a socket and ratchet to carefully remove the spark plug.
  4. Inspect the old spark plug for wear or carbon buildup.
  5. If necessary, replace with a new spark plug that meets OEM specifications (typically, NGK or Denso).
  6. Torque the new spark plug to the manufacturer's specified value (usually around 13-15 lb-ft).
  7. Reconnect the ignition coil.

3. Check and Replace Ignition Coil

• Sub-steps:
  1. If the spark plug is in good condition, remove the ignition coil from cylinder 1.
  2. Inspect the coil for cracks or damage.
  3. Replace the ignition coil if necessary, ensuring it matches OEM specifications.
  4. Reconnect the ignition coil securely.

4. Fuel Injector Inspection

• Sub-steps:
  1. Remove the fuel injector rail, taking care to relieve fuel pressure first.
  2. Inspect the fuel injector for cylinder 1 for clogs or malfunction.
  3. Test the injector using a multimeter to ensure it is receiving the correct voltage and is functioning properly.
  4. Replace the injector if it is faulty.

5. Compression Test

• Sub-steps:
  1. Remove the spark plug for cylinder 1 again.
  2. Connect a compression gauge to the spark plug hole.
  3. Crank the engine for several seconds and record the compression reading.
  4. Compare the reading with specifications for your engine (typically around 180-200 psi).
  5. If compression is low, further investigation may be required.