what does P0300 code mean for my Toyota Highlander Fourth Generation (2020-present)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plugs

• Remove the spark plug wires or ignition coil packs.
• Use a spark plug socket to remove each spark plug.
• Inspect the condition; replace with OEM spark plugs if worn or damaged.
  • Torque new spark plugs to the manufacturer’s specification (typically around 13-15 ft-lbs).

3. Test and Replace Ignition Coils (if necessary)

• Use a multimeter to check the resistance of each ignition coil.
• If any coils are outside the specified range, replace them with OEM parts.
• Reinstall the ignition coils and ensure they are seated properly.

4. Check Fuel Injectors

• Perform a fuel pressure test using a fuel pressure gauge to ensure it meets specifications (typically 50-60 psi).
• Clean or replace clogged fuel injectors as necessary.

5. Inspect for Vacuum Leaks

• Visually inspect all vacuum lines for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to identify any leaks around the intake manifold or vacuum lines.
• Repair or replace any damaged components.

6. Perform Compression Test

• Remove spark plugs and insert a compression tester into each cylinder.
• Crank the engine and record the compression readings; they should be within manufacturer specifications.
• Address any cylinders with low compression, which may require further diagnosis.