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

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the negative terminal of the battery to prevent electrical shock.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench, gap tool.
• Remove the ignition coil from cylinder 3 by disconnecting the electrical connector and unbolting it.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary.
• Gap the new spark plug according to manufacturer specifications.
• Install the new spark plug and torque it to the manufacturer's recommended specification (typically 13-16 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil (if needed)

• If the ignition coil appears damaged or if the spark plug replacement did not resolve the issue, replace the ignition coil for cylinder 3.
• Tools Required: Ratchet, socket set.
• Remove the faulty ignition coil as previously described.
• Install a new ignition coil in the reverse order of removal, ensuring it is seated properly.

4. Inspect and Test Fuel Injector

• Tools Required: Noid light or multimeter.
• Disconnect the fuel injector connector for cylinder 3.
• Use a noid light to check for signal at the injector connector; if there is no signal, check wiring and ECM.
• If the injector is faulty, replace it by removing the fuel rail if needed and installing a new injector.

5. Reassemble and Final Checks

• Ensure all components are reconnected and secured.
• Reconnect the battery terminal.
• Start the engine and allow it to idle for a few minutes.