what to do if my Toyota RAV4 XA40 (2013-2018) has a check engine light and error code P0301?

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, socket set, torque wrench, compression tester, fuel injector cleaner, new spark plug, new ignition coil (if needed).
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Locate the spark plug for cylinder 1 (usually the front of the engine).
• Remove the ignition coil by unscrewing the bolts and unplugging the electrical connector.
• Remove the old spark plug using a spark plug socket.
• Inspect the spark plug for fouling or wear. If damaged, replace it with a new spark plug, making sure to gap it according to manufacturer specifications.
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test and Clean Fuel Injector

• Remove the fuel injector for cylinder 1 by disconnecting the electrical connector and unscrewing it from the intake manifold.
• Inspect for clogs or deposits. If dirty, clean the injector with a fuel injector cleaner or replace it if damaged.
• Reinstall the fuel injector and ensure it is properly seated and secured.

4. Conduct Compression Test

• Remove the spark plug for cylinder 1 again to access the cylinder.
• Insert the compression tester into the spark plug hole.
• Crank the engine several times and record the compression reading. Compare it to the manufacturer's specifications.
• If compression is low, further investigation for potential internal engine issues may be required.

5. Final Assembly

• Reassemble any components removed during the inspection and repairs.
• Reconnect the battery.
• Start the engine and monitor for any unusual sounds or issues.