how to fix P0300 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

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

2. Replace Spark Plugs

1. Remove the engine cover (if applicable) using a socket set.
2. Disconnect electrical connectors from each ignition coil.
3. Remove the ignition coils using a socket wrench.
4. Unscrew the old spark plugs with a spark plug socket and inspect for wear.
5. Install new spark plugs, ensuring correct torque (usually around 13-15 ft-lbs).
6. Reinstall ignition coils and reconnect electrical connectors.

3. Inspect and Replace Ignition Coils (if needed)

1. If the ignition coils show signs of damage, replace them as follows:
2. Remove old ignition coils as described above.
3. Install new ignition coils, ensuring they are seated properly.
4. Reconnect the electrical connectors to each coil.

4. Check Fuel Injectors

1. Use a fuel pressure gauge to check if the fuel pressure is within specifications (usually around 50-60 psi).
2. If pressure is low, inspect the fuel filter and replace if clogged.
3. If injectors are faulty, remove and clean them or replace as necessary.

5. Inspect Vacuum Lines

1. Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
2. Replace any damaged vacuum lines.