how to diagnose P0303 code on Ford F-150 14th Generation (2021-2024)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 (2021-2024). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

• Remove the engine cover if necessary.
• Use a socket wrench to remove the ignition coil from cylinder 3.
• Carefully pull out the spark plug using a spark plug socket.
• Inspect the old spark plug; if it is worn or damaged, replace it.
• Install the new spark plug and torque it to manufacturer specifications (typically around 13-15 ft-lbs).
• Reinstall the ignition coil onto the spark plug ensuring it is seated properly.

3. Inspect and Replace Ignition Coil (if needed)

• If the ignition coil appears damaged or if misfires persist after spark plug replacement, proceed to replace the ignition coil.
• Disconnect the wiring harness from the ignition coil.
• Remove the ignition coil using a socket wrench.
• Install the new ignition coil and reconnect the wiring harness.

4. Check Fuel Injector

• Locate the fuel injector for cylinder 3 and disconnect the electrical connector.
• Use a multimeter to test the resistance of the fuel injector (should be within manufacturer specifications).
• If the injector is faulty, remove it using a fuel injector puller and replace it with a new one.
• Reconnect the electrical connector and ensure proper wiring.

5. Clear Codes and Test

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0303 code.
• Start the engine and allow it to reach operating temperature.
• Test drive the vehicle to ensure the misfire has been resolved.