how to fix P0303 misfire code on my Toyota RAV4 XA50 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down for safety.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector from the spark plug.
• Remove the ignition coil using a socket.
• Unscrew and remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear; replace it if it shows signs of fouling or damage.
• Install a new spark plug, torque to manufacturer's specifications (typically around 13-15 lb-ft).
• Reinstall the ignition coil and connector.

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• If the spark plug inspection is fine, test the ignition coil with a multimeter for resistance.
• If faulty, remove the ignition coil from cylinder 3.
• Install a new ignition coil, ensuring it is seated properly; torque to manufacturer's specifications.

4. Inspect Fuel Injector

• Tools Required: Fuel injector removal tool, socket set.
• Disconnect the fuel injector connector from cylinder 3.
• Remove the fuel rail if necessary to access the fuel injector.
• Inspect the fuel injector for clogs; clean or replace if needed.
• Reinstall the fuel injector and fuel rail, ensuring all connections are tight.

5. Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 3.
• Insert the compression tester into the spark plug hole.
• Crank the engine and note the compression reading. It should match the manufacturer’s specifications (typically around 150 psi or higher).
• If the compression is low, further inspection of valves and piston rings may be necessary.