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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, vacuum gauge, jack and jack stands.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors (if faulty)

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket wrench to remove the oxygen sensors from the exhaust pipe.
3. Inspect the sensors for damage; replace if necessary.
4. Install new oxygen sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 ft-lbs).
5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if faulty)

1. Remove any heat shields or covers obstructing access to the catalytic converter.
2. Unbolt the catalytic converter from the exhaust system (both upstream and downstream connections).
3. Inspect the catalytic converter for signs of physical damage or clogging.
4. If replacement is needed, install the new catalytic converter and ensure all bolts are torqued to specification (usually around 40 ft-lbs).
5. Reattach any heat shields or covers.

4. Clear Codes and Test Drive

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code from the engine control module.
3. Perform a test drive under various conditions to ensure the code does not reappear.