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

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench
• Remove the ignition coil from cylinder 1:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the mounting bolts and carefully lift out the coil.
• Remove the spark plug:
  1. Use a spark plug socket to unscrew the spark plug from cylinder 1.
  2. Inspect the spark plug for wear or fouling.
• Replace with a new spark plug:
  1. Gap the new spark plug to manufacturer specifications.
  2. Install the spark plug and torque it to the manufacturer's specifications (typically around 13-15 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if needed)

• If the ignition coil is found to be faulty:
  1. Remove the ignition coil as described in step 2.
  2. Install a new ignition coil and secure it with the mounting bolts.
  3. Reconnect the electrical connector.

4. Check and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit (if cleaning is necessary)
• Remove the fuel injector from cylinder 1:
  1. Disconnect the electrical connector from the fuel injector.
  2. Remove any retaining clips and carefully pull out the injector.
• Clean or replace the fuel injector as needed:
  1. If cleaning, follow the injector cleaning kit instructions.
  2. If replacement is necessary, install a new injector and ensure it is seated properly.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0301 code from the system.