how to fix P0301 misfire code on my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather all 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 shorts.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1 by unbolting it and disconnecting the electrical connector.
• Extract the spark plug using a socket and ratchet.
• Inspect the spark plug for signs of wear, such as excessive carbon buildup or damage.
• If worn, replace it with a new spark plug that meets OEM specifications (usually NGK or Denso).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, inspect the ignition coil for cracks or signs of arcing.
• If defective, replace the ignition coil with a new unit that meets OEM specifications.
• Reinstall the ignition coil over the new spark plug and reattach the electrical connector.

4. Test Fuel Injector

• If the misfire persists, remove the fuel injector from cylinder 1.
• Use a noid light to check for proper electrical pulse to the injector when the engine is cranked.
• If there is no pulse, check wiring and connectors; if everything checks out, replace the fuel injector.

5. Reassemble and Reconnect

• Reattach all components, ensuring connectors are secured and bolts are torqued to the manufacturer’s specifications.
• Reconnect the negative battery terminal.

6. Clear Codes and Test Drive

• Use the OBD-II scanner to clear the P0301 code.
• Start the engine and monitor for smooth operation; perform a test drive to ensure the issue is resolved.