how to fix P0300 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, fuel pressure gauge, multimeter.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting any work.

2. Inspect and Replace Spark Plugs

• Remove the ignition coil covers (if applicable) to access the spark plugs.
• Use a socket and ratchet to remove the spark plugs.
• Inspect the spark plugs for wear or damage. Replace with OEM specifications if necessary.
  • Torque specification: 13 lb-ft (17.6 Nm) for spark plugs.
• Reinstall ignition coils ensuring secure connections.

3. Test and Replace Ignition Coils (if necessary)

• Use a multimeter to test the resistance of each ignition coil.
• If any coils are out of specification, replace them using the following steps:
  • Disconnect the electrical connector from the faulty coil.
  • Remove the mounting bolts and take out the ignition coil.
  • Install the new ignition coil and reconnect the electrical connector.

4. Check and Replace Fuel Injectors (if necessary)

• Inspect the fuel injectors for clogs or leaks.
• To replace a faulty injector:
  • Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
  • Disconnect the fuel lines and electrical connectors from the injector.
  • Remove mounting bolts and take out the injector.
  • Install the new injector with new O-rings, ensuring proper seating.
  • Reconnect fuel lines and electrical connectors securely.

5. Inspect and Repair Air Intake System

• Check for any vacuum leaks in hoses or intake manifold.
• Clean the mass airflow sensor using a specialized cleaner if it appears dirty.
• Ensure the air filter is clean and replace if necessary.

6. Perform Compression Test (if misfires persist)

• Remove all spark plugs.
• Insert a compression tester into each cylinder and crank the engine.
• Record the compression readings and compare them to manufacturer specifications.
• If compression is low, further investigation into internal engine problems may be necessary.