how to fix P0303 code in Ford F-150 12th Generation (2009-2014)

Learn how to diagnose and fix P0303 cylinder 3 misfire in Ford F-150 12th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, spark plug socket, compression tester, fuel injector tester, basic hand tools.
• Disconnect the battery to avoid any electrical shorts.

2. Spark Plug Replacement

1. Remove the engine cover if applicable.
2. Locate the spark plug for cylinder three.
3. Use a spark plug socket and ratchet to remove the spark plug.
4. Inspect the spark plug for damage such as carbon buildup or wear.
5. Install a new spark plug (OEM specifications recommended).
   • Torque the new spark plug to 13 lb-ft (17.5 Nm).
6. Reconnect the ignition coil.

3. Ignition Coil Check

1. Disconnect the electrical connector from the ignition coil for cylinder three.
2. Use a multimeter to test the primary and secondary resistance of the ignition coil.
   • Primary resistance should be between 0.4 to 2 ohms.
   • Secondary resistance should be between 6,000 to 15,000 ohms.
3. If the ignition coil is faulty, replace it with a new one.
4. Reconnect the ignition coil and electrical connector.

4. Fuel Injector Testing

1. Disconnect the fuel injector connector from cylinder three.
2. Use a fuel injector tester to check if the injector is firing.
3. If the injector is not functioning, replace it.
4. Reconnect the fuel injector connector.

5. Compression Test

1. Remove the spark plug from cylinder three.
2. Insert a compression tester into the spark plug hole.
3. Crank the engine for a few seconds and read the compression value.
   • A healthy cylinder should show values between 120-180 psi.
4. If the compression is low, further investigation into potential mechanical issues (such as valves or piston rings) is necessary.