how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

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

2. Oxygen Sensor Replacement (if needed)

1. Locate the oxygen sensors: The pre-catalytic sensor is located before the catalytic converter, and the post-catalytic sensor is after it.
2. Disconnect the electrical connectors from both oxygen sensors.
3. Use a socket wrench to remove the oxygen sensors from their mounting locations.
4. Install the new oxygen sensors: Apply anti-seize compound to the threads and torque to manufacturer specifications (usually around 30 lb-ft).
5. Reconnect the electrical connectors.

3. Catalytic Converter Inspection/Replacement

1. Inspect the catalytic converter for any visible signs of damage or clogging.
2. If replacement is necessary, use a socket set to remove the flange bolts or clamps securing the catalytic converter to the exhaust system.
3. Carefully remove the old catalytic converter and replace it with a new unit, ensuring correct orientation.
4. Reinstall the bolts or clamps and torque to manufacturer specifications (typically around 40 lb-ft).
5. Reconnect any exhaust hangers that were disconnected during the process.

4. Final Checks

1. Reconnect the battery terminal.
2. Start the engine and allow it to reach operating temperature. Check for exhaust leaks around the newly installed components.
3. Clear the P0420 code using the OBD-II scanner and take the vehicle for a test drive to ensure the code does not return.