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

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

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, dielectric grease.
• Remove the ignition coil for cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the mounting bolts and lift the coil out.
• Remove the spark plug:
  1. Use a spark plug socket to unscrew and remove the spark plug from cylinder 3.
  2. Inspect the old spark plug for signs of wear or carbon buildup.
• Install the new spark plug:
  1. Apply a small amount of dielectric grease to the spark plug threads.
  2. Torque the spark plug to the manufacturer's specification (typically around 13-16 lb-ft).
• Reinstall the ignition coil:
  1. Position the coil back into place and secure it with bolts.
  2. Reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

• Tools Required: Socket set.
• If the ignition coil is faulty, remove it as previously described.
• Install a new ignition coil in its place.
• Reconnect the electrical connector.

4. Inspect or Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector removal tool, cleaning solvent.
• If the fuel injector is suspected to be faulty, remove it from cylinder 3:
  1. Relieve fuel system pressure.
  2. Disconnect the fuel line and electrical connector from the injector.
  3. Remove the retaining clips and pull the injector out.
• Clean the injector or replace it with a new one if necessary.
• Ensure proper installation and reconnect all lines and connectors.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0303 code and any other stored codes.