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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is off and cooled down.
• Disconnect the negative battery terminal for safety.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1.
  • Tools: Socket set, ratchet
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for fouling, wear, or damage.
• Replace with a new spark plug (follow manufacturer’s specifications for gap).
• Reinstall the spark plug and ignition coil.

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil.
  • Tools: Multimeter
• Measure the resistance of the ignition coil; compare with specifications.
• If the ignition coil is faulty, replace it with a new one.
• Reconnect the ignition coil.

4. Inspect Fuel Injector

• Remove the fuel rail to access the injector for cylinder 1.
  • Tools: Fuel line removal tool, socket set
• Test the fuel injector operation (using a noid light or by measuring resistance).
• If faulty, replace the fuel injector with a new one.
• Reassemble the fuel rail.

5. Perform Compression Test

• Remove the spark plug from cylinder 1.
• Insert a compression tester into the spark plug hole.
• Crank the engine and record the compression reading.
• If the reading is below specifications, further investigation into the engine internals may be needed.

6. Inspect for Vacuum Leaks

• Use a smoke machine or spray soapy water around intake manifold and hoses while the engine is running.
• Look for bubbles or smoke indicating leaks.
• Repair or replace any damaged hoses or gaskets.