how to fix P0303 code in Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 3.
  • Unscrew the bolts securing the coil and gently pull it out.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear or damage. If fouled or worn, replace it.
  • Torque the new spark plug to the manufacturer's specification (typically 13-16 ft-lbs).

3. Test and Replace Ignition Coil (if necessary)

• Tools Required: Multimeter.
• Test the ignition coil's resistance:
  • Check primary resistance (should be around 0.4-0.8 ohms).
  • Check secondary resistance (should be around 6,000-15,000 ohms).
• If the ignition coil is out of specification, replace it with a new one.
  • Reinstall the ignition coil by aligning it properly and tightening the screws to the specified torque.

4. Check and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, injector puller (if needed).
• If the injector is suspected of being clogged, clean it using a fuel injector cleaning kit or replace it.
• Reconnect the fuel injector, ensuring a snug connection.

5. Reassemble and Test

• Reconnect the negative battery terminal.
• Start the engine and check for any warning lights.
• Test drive the vehicle to ensure the issue is resolved.