how to fix P0300 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, socket set, compression tester, fuel pressure gauge, replacement spark plugs, ignition coils (if needed), and cleaning solvent for fuel injectors.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Spark Plugs

1. Remove the engine cover (if applicable) using a socket wrench.
2. Disconnect the ignition coils from the spark plugs by removing the connector clips.
3. Use a spark plug socket to remove the spark plugs from the engine.
4. Inspect the spark plugs for wear. Replace any damaged or worn plugs with OEM or high-quality aftermarket plugs, ensuring the gap is set to the manufacturer's specifications.
5. Reinstall the spark plugs and ignition coils, ensuring they are securely connected.

3. Check and Replace Ignition Coils (if necessary)

1. If the ignition coils are found to be faulty during inspection, remove them from the engine by unbolting them (usually 10mm bolts).
2. Replace with new ignition coils, ensuring they match the original part specifications.
3. Reconnect the ignition coil connectors.

4. Clean or Replace Fuel Injectors

1. If fuel injectors are suspected to be clogged, remove them from the engine (typically requires removing the fuel rail).
2. Clean the injectors with a professional cleaning kit or replace them if severely clogged.
3. Reinstall the fuel injectors and ensure all connections are tight.

5. Test and Repair Vacuum Leaks

1. Inspect hoses connected to the intake manifold for cracks or disconnections.
2. Use a smoke machine or carburetor cleaner to check for leaks. If a leak is found, replace the affected hose.
3. Reassemble any components removed during the inspection.

6. Verify Fuel Pressure

1. Connect a fuel pressure gauge to the fuel rail’s test port.
2. Start the engine and monitor the pressure. Compare readings to manufacturer specifications. If pressure is low, check the fuel pump and filter for issues.