how to diagnose P0420 code on Ford F-150 Fourteenth Generation (2021-present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery for safety.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Replace Faulty Oxygen Sensors (if needed)

1. Locate the upstream and downstream oxygen sensors.
2. Use a wrench to disconnect the electrical connectors.
3. Unscrew the oxygen sensors using an oxygen sensor socket.
4. Install new oxygen sensors by screwing them in and reconnecting the electrical connectors.
   • Torque: Follow manufacturer specifications for torque values during installation.

3. Replace Catalytic Converter (if necessary)

1. Remove the exhaust system components leading to the catalytic converter, including any heat shields.
2. Unscrew the bolts securing the catalytic converter to the exhaust manifold and exhaust pipe.
3. Remove the catalytic converter from its mounting location.
4. Install the new catalytic converter, ensuring the alignment is correct.
5. Reattach any exhaust system components and heat shields.
   • Torque: Again, follow manufacturer specifications for all bolts.

4. Clear Error Codes

1. Reconnect the negative terminal of the battery.
2. Use the OBD-II scanner to clear any stored error codes.
3. Start the engine and let it idle for a few minutes.