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

Solution

1. Preparation

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

2. Oxygen Sensor Replacement (if faulty)

1. Locate the upstream and downstream oxygen sensors.
2. Use a socket wrench to unscrew the faulty oxygen sensor.
3. Apply anti-seize compound to the threads of the new oxygen sensor.
4. Install the new oxygen sensor and tighten it to the manufacturer's specified torque (typically around 30 ft-lbs).
5. Reconnect the electrical connector to the oxygen sensor.

3. Catalytic Converter Replacement (if necessary)

1. Remove the exhaust system components connected to the catalytic converter; this may involve loosening clamps and removing bolts.
2. If applicable, remove the oxygen sensors from the catalytic converter.
3. Detach the catalytic converter from the exhaust pipe and/or exhaust manifold.
4. Install the new catalytic converter, ensuring that any gaskets or seals are replaced.
5. Reinstall the exhaust system components and tighten all bolts to the manufacturer's specifications.
6. Reinstall the oxygen sensors if removed earlier.

4. Resetting the Engine Control Module (ECM)

1. Reconnect the negative battery terminal.
2. Start the engine and let it idle for a few minutes.
3. Use an OBD-II scanner to clear the P0420 code from the ECM.