why does my Toyota RAV4 XA40 (2013-2018) have a check engine code P0301?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool before starting work.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil connector from the cylinder 1 ignition coil.
  3. Unbolt the ignition coil using a socket wrench and carefully remove it.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for wear or damage; replace if necessary.
  6. Install the new spark plug to the manufacturer's specified torque (typically 13-16 ft-lbs).
  7. Reinstall the ignition coil and its connector.

3. Inspect and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. If the spark plug is in good condition, test the ignition coil using a multimeter.
  2. If the coil is faulty, remove it as described above.
  3. Install the new ignition coil and reconnect the connector.

4. Check and Replace Fuel Injector (if necessary)

• Sub-steps:
  1. Remove the fuel rail cover (if applicable).
  2. Disconnect the fuel line and electrical connector from the fuel injector.
  3. Remove the retaining clips and pull out the fuel injector.
  4. Inspect for clogs or damage; replace if necessary.
  5. Reinstall the new fuel injector, ensuring proper seating and connections.

5. Perform Compression Test (if misfire persists)

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert the compression gauge into the spark plug hole.
  3. Crank the engine to take a reading and compare it to manufacturer specifications.
  4. If compression is low, further diagnosis is required for internal engine issues.