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, exhaust pipe cutter, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is cool before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Find the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Disconnect the Battery: Disconnect the negative battery terminal to avoid electrical shorts.
3. Remove the Sensors: Use the appropriate socket to unscrew the sensors from the exhaust system.
4. Inspect the Sensors: Check for damage or contamination. If they are faulty, replace them with OEM or equivalent sensors.
5. Install New Sensors: Screw in the new sensors and connect the wiring harness. Torque to manufacturer specifications.

3. Inspect and Replace the Catalytic Converter

1. Check for Damage: Visually inspect the catalytic converter for dents, cracks, or rust.
2. Remove Exhaust Components: Using the exhaust pipe cutter, cut the exhaust pipes connected to the catalytic converter. Ensure to wear safety glasses and gloves.
3. Remove the Old Catalytic Converter: Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
4. Install New Catalytic Converter: Position the new catalytic converter and secure it with bolts to the manifold and exhaust pipe. Torque to manufacturer specifications.
5. Reconnect Exhaust System: Reattach any removed exhaust components and ensure all connections are tight.

4. Final Checks

• Reconnect the battery terminal.
• Clear any diagnostic trouble codes using the OBD-II scanner.
• Start the engine and inspect for any exhaust leaks.