how to fix the check engine light on my Toyota RAV4 XA40 (2013-2018) with P0301?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if it has been recently running.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts.
• Carefully pull the ignition coil out to access the spark plug.
• Using a spark plug socket, remove the old spark plug from cylinder 1.
• Install the new spark plug, tightening it to the manufacturer’s specified torque (usually around 13-15 lb-ft).
• Reinstall the ignition coil and secure it with bolts.

3. Check/Replace Ignition Coil

• Tools Required: Multimeter, socket set.
• Test the ignition coil using a multimeter set to ohms; check the primary and secondary resistance according to specifications.
• If out of range, replace the ignition coil with a new one.
• Reinstall the new ignition coil, ensuring it is properly seated.

4. Inspect/Replace Fuel Injector

• Tools Required: Fuel injector puller, socket set.
• Remove the fuel rail if necessary to access the fuel injector for cylinder 1.
• Inspect the fuel injector for clogs or leaks; clean or replace if necessary.
• Reinstall the fuel rail and ensure all connections are secure.

5. Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1 and connect the compression tester.
• Crank the engine and record the compression reading. Compare to manufacturer specifications.
• If compression is low, further investigation is required for potential internal engine issues.