how to fix P0300 code in my 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 before starting work.

2. Inspect and Replace Spark Plugs

• Remove the spark plug wire or ignition coil from the first cylinder.
• Use a spark plug socket to remove the spark plug.
• Inspect the spark plug for wear; replace if necessary using OEM specifications (usually NGK or Denso for Toyota).
• Torque the new spark plug to the manufacturer's specification (typically around 13 ft-lbs).
• Repeat for all cylinders as necessary.

3. Check and Replace Ignition Coils

• Access the ignition coils by removing any necessary engine covers.
• Disconnect the electrical connector from each ignition coil.
• Remove the ignition coil using a socket set.
• Test each coil with a multimeter according to specifications (typically 0.4-0.6 ohms).
• Replace any faulty coils with OEM parts and reconnect the electrical connectors.

4. Clean or Replace Fuel Injectors

• If injectors are suspected to be clogged, use a fuel injector cleaning kit or replace them.
• To clean, disconnect the fuel rail and remove the injectors.
• Follow the kit instructions for cleaning.
• If replacing, install new OEM injectors and ensure proper sealing.

5. Conduct a Compression Test

• Remove spark plugs for easier access to cylinders.
• Insert a compression gauge into the spark plug hole.
• Crank the engine and record the compression reading for each cylinder.
• Compare readings to manufacturer specifications (typically 150-200 psi).
• Address any cylinders with low compression (possible head gasket leak or valve issues).