how to fix P0420 code in Ford F-150 13th Generation (2015-2020)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust pipe.
  4. Install the new oxygen sensors by threading them into the exhaust and tightening to manufacturer specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors firmly.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter and inspect for any visible damage or blockages.
  3. If replacement is necessary, use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
  4. Remove the old catalytic converter and clean the mating surface on the exhaust pipe.
  5. Install the new catalytic converter with new gaskets, ensuring all bolts are tightened to manufacturer specifications (typically 25 lb-ft).

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the error codes.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive for at least 20 minutes to ensure the check engine light does not reappear.