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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery cable to prevent electrical shock.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge, dielectric grease.
• Remove the engine cover if applicable.
• Use a socket to remove the spark plug from cylinder 3.
• Inspect the spark plug for wear or damage; replace if necessary.
• Check the spark plug gap using a gap gauge and adjust to the manufacturer’s specifications (typically around 0.043 inches for many Toyota models).
• Apply a small amount of dielectric grease to the threads of the new spark plug.
• Install the new spark plug and torque to the manufacturer’s specifications (usually around 13-16 lb-ft).

3. Replace Ignition Coil

• Tools Required: Socket set, ratchet.
• Remove the ignition coil connector by pressing the tab and pulling it off.
• Unscrew the ignition coil mounting bolts and remove the coil from cylinder 3.
• Install the new ignition coil, ensuring it is seated properly.
• Reattach the ignition coil connector.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaner or cleaning kit.
• Remove the fuel injector rail if necessary to access the injector for cylinder 3.
• Inspect the injector for carbon buildup or blockage.
• Clean the injector using a fuel injector cleaning kit or replace it if damaged.

5. Reassemble and Reconnect Battery

• Reattach any components removed during the repair (e.g., engine cover, fuel rail).
• Reconnect the negative battery cable.
• Start the engine to ensure proper operation.