how to fix P0303 misfire code in Toyota Corolla E140 (2006-2013)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Toyota Corolla E140 (2006-2013). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

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

2. Replace Spark Plug and Ignition Coil

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector from cylinder 3.
• Remove the ignition coil bolt and carefully pull out the ignition coil.
• Remove the spark plug using the spark plug socket and inspect it for wear.
• Install the new spark plug, tightening it to the manufacturer's specification (typically around 13-20 lb-ft).
• Reinstall the ignition coil and bolt, ensuring it is securely fastened.
• Reconnect the ignition coil connector.

3. Check and Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector puller (if necessary), socket set
• If the injector is not functioning, disconnect the fuel injector connector.
• Remove the fuel rail bolts and carefully lift the fuel rail to extract the injector.
• Replace the faulty injector with a new one, ensuring proper O-ring placement.
• Reattach the fuel rail and bolts, taking care to not damage any components.

4. Verify Compression (if needed)

• Tools Required: Compression tester
• Remove the spark plug from cylinder 3 and install the compression tester.
• Crank the engine and take note of the compression reading.
• If compression is low, further diagnosis is needed to check for internal engine issues.