how to fix P0303 code on my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety during repairs.
• Allow the engine to cool before starting work.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 3:
  • Disconnect the electrical connector and remove bolts.
  • Pull the coil out gently.
• Remove the spark plug using a spark plug socket:
  • Use a ratchet and extension to reach the spark plug.
  • Inspect the removed spark plug for wear; replace if necessary.
• Install the new spark plug:
  • Torque to manufacturer's specification (typically around 13-16 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test Ignition Coil

• If the ignition coil was found faulty in diagnostics:
  • Remove the coil and install a new one.
  • Ensure that the coil is properly seated and connected.

4. Check Fuel Injector

• If the fuel injector was suspected:
  • Disconnect the fuel line and electrical connector from the injector.
  • Remove the injector using the appropriate tool.
  • Replace with a new injector if necessary.
  • Reconnect the fuel line and electrical connector securely.

5. Reassemble and Test

• Reconnect the battery terminal.
• Start the engine and allow it to reach operating temperature.
• Clear the P0303 code using the OBD-II scanner and check if it returns after a test drive.