why does my Toyota Highlander Third Generation (2014-2019) check engine light flash while driving

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.
• Allow the engine to cool if it has been running.

2. Address Ignition System Issues

• Spark Plug Replacement:

  • Remove the ignition coils to access the spark plugs.
  • Use a spark plug socket to remove the old spark plugs.
  • Install new spark plugs, ensuring they are gapped to the manufacturer’s specifications (usually around 0.043 inches).
  • Torque the spark plugs to the specified value (typically around 13 ft-lbs).

• Ignition Coil Replacement:

  • Inspect each ignition coil for cracks or damage.
  • Replace any faulty ignition coils by disconnecting the electrical connector and removing the mounting screws.

3. Repair Fuel System

• Fuel Filter Replacement:

  • Locate and remove the old fuel filter, carefully releasing any pressure in the fuel lines beforehand.
  • Install a new fuel filter, ensuring proper orientation and secure connections.

• Fuel Pump Testing:

  • Use a fuel pressure gauge to check if the fuel pump is providing adequate pressure (around 40-50 psi is typical).
  • Replace the fuel pump if pressure is below specifications.

4. Inspect Air Intake and Sensors

• Mass Airflow Sensor Cleaning:

  • Remove the MAF sensor from the air intake duct.
  • Use MAF sensor cleaner to clean the sensor element carefully.
  • Reinstall the MAF sensor securely.

• Check for Vacuum Leaks:

  • Inspect all hoses connected to the intake manifold for cracks or disconnections.
  • Replace any damaged hoses and ensure all connections are tight.

5. Clear Codes and Test Drive

• Use the OBD-II scanner to clear any stored trouble codes.
• Start the engine and take the vehicle for a test drive to monitor engine performance and ensure that the check engine light does not reappear.