how to fix P0301 code on Toyota RAV4 XA40 (2013-2018) that causes misfires?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool completely before beginning work.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1 by unscrewing the bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket and ratchet.
• Inspect the old spark plug for signs of wear or fouling.
• Install the new spark plug, tightening it to the manufacturer’s specified torque (typically around 13-15 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Replace Ignition Coil (if necessary)

• Use a multimeter to measure the resistance of the ignition coil for cylinder 1. The primary resistance should typically be between 0.4 to 2.0 ohms, and the secondary resistance should be between 6,000 to 15,000 ohms.
• If the ignition coil fails the test, replace it with a new one, ensuring to secure it properly and reconnect the electrical connector.

4. Inspect and Clean/Replace Fuel Injector (if necessary)

• Remove the fuel injector from cylinder 1 using a fuel injector puller or appropriate tools.
• Inspect the injector for clogs or damage. Clean it using an ultrasonic cleaner or replace it if necessary.
• Reinstall the injector, ensuring it is seated properly and reconnecting the fuel line.

5. Verify Vacuum Leaks

• Inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to check for vacuum leaks while the engine is running. Repair or replace any damaged lines.