how to fix Ford Explorer Fifth Generation (2011-2019) check engine light with P0420 code

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle battery to ensure safety.
• Allow the vehicle to cool down if the engine has been running.

2. Oxygen Sensor Replacement (if faulty)

• Tools Required: Oxygen sensor socket, wrench set, safety gloves.
• Remove the negative battery cable.
• Locate the pre-catalytic and post-catalytic oxygen sensors.
• Use the oxygen sensor socket to unscrew the faulty sensor.
• Apply anti-seize compound to the threads of the new sensor.
• Install the new oxygen sensor and torque it to the manufacturer's specifications (typically around 30 lb-ft).
• Reconnect the negative battery cable.

3. Catalytic Converter Replacement (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed), new gaskets.
• Raise the vehicle with a jack and secure it on jack stands.
• Remove the exhaust assembly bolts connecting to the catalytic converter.
• If necessary, cut the pipes leading to the catalytic converter using an exhaust pipe cutter.
• Remove the old catalytic converter from the exhaust system.
• Install the new catalytic converter with new gaskets, ensuring proper alignment.
• Torque the bolts to the manufacturer's specifications (typically around 25 lb-ft).
• Reassemble any removed exhaust components.

4. Clearing the Codes

• Tools Required: OBD-II scanner.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Start the engine and allow it to reach operating temperature.