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

Solution

1. Preparation

• Gather necessary tools and materials.
• Disconnect the battery negative terminal.
• Ensure the engine is cool before starting work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for fouling or damage; replace if necessary.
• Torque the new spark plug to the manufacturer’s specification (typically around 13-16 lb-ft).

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil for cylinder 1.
• Replace the ignition coil if it does not meet resistance specifications (typically 0.5-2.0 ohms for primary resistance).
• Reinstall the ignition coil and ensure it’s seated properly.

4. Inspect Fuel Injector

• Remove the fuel rail to access the fuel injector for cylinder 1.
• Test the injector resistance with a multimeter; it should be within manufacturer specifications (typically around 12-16 ohms).
• If faulty, replace the fuel injector and ensure proper installation.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to detect leaks around the intake manifold.
• Repair or replace any damaged hoses or gaskets.

6. Final Assembly

• Reassemble all components in reverse order.
• Reconnect the battery terminal.
• Start the engine and ensure it runs smoothly.