how to diagnose P0301 misfire code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

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

2. Replace Spark Plug

• Step 1: Remove the ignition coil from cylinder 1.
• Step 2: Use a spark plug socket to remove the spark plug.
• Step 3: Inspect the spark plug; if damaged or worn, replace it with a new one (OEM specifications recommended).
• Step 4: Torque the new spark plug to the manufacturer's specifications (typically 13-16 lb-ft).

3. Replace Ignition Coil (if necessary)

• Step 1: If the ignition coil is found to be faulty, remove the coil from cylinder 1.
• Step 2: Install a new ignition coil and ensure it is seated properly.
• Step 3: Reconnect the electrical connector to the ignition coil.

4. Fuel Injector Replacement (if needed)

• Step 1: If the fuel injector is not functioning properly, remove the fuel rail from the engine.
• Step 2: Disconnect the fuel injector wiring harness.
• Step 3: Remove the old fuel injector and replace it with a new one.
• Step 4: Reinstall the fuel rail and ensure all connections are secure.

5. Clear Codes and Test

• Step 1: Reconnect the negative battery terminal.
• Step 2: Use the OBD-II scanner to clear the P0301 code.
• Step 3: Start the engine and allow it to reach operating temperature.