my Toyota RAV4 XA50 (2019-2024) has a check engine light and P0301 code

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Unbolt and remove the ignition coil.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for wear or carbon buildup; replace if necessary with the recommended type (e.g., NGK or Denso).
  6. Reinstall the spark plug and torque it to the manufacturer's specifications (typically around 13-16 lb-ft).
  7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Test Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a multimeter to test the injector's resistance (typically around 12-16 ohms).
  3. If the injector fails the resistance test, replace it with a new OEM or equivalent injector.
  4. Reconnect the fuel injector connector.

4. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Install the compression gauge into the spark plug hole.
  3. Crank the engine for a few seconds and record the pressure reading.
  4. Compare the reading to the manufacturer's specifications (typically around 180-200 psi). If low, further diagnostics may be required.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0301 code.
• Start the engine and observe for any reoccurrence of the check engine light.