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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery (negative terminal) to avoid electrical shock.
• Raise the vehicle securely on jack stands if accessing the exhaust system from underneath.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
• Disconnect the wiring harness from each sensor.
• Use the O2 sensor socket to remove the sensors from the exhaust manifold and exhaust pipe, respectively.
• Install the new sensors by threading them into the respective locations and tightening to the manufacturer’s specified torque (usually around 30 ft-lbs).
• Reconnect the wiring harness.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, cutting tools if necessary, gasket scraper, exhaust sealant.
• If the catalytic converter is damaged or clogged, it will need replacement.
• Disconnect the exhaust pipes leading to and from the catalytic converter.
• Remove any mounting bolts or brackets securing the catalytic converter.
• Carefully remove the old catalytic converter.
• Clean the mating surfaces on the exhaust pipes to ensure a proper seal.
• Install the new catalytic converter, securing it with bolts and brackets, and use new gaskets if required.
• Apply exhaust sealant if necessary.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code from the ECM.
• Take the vehicle for a test drive to ensure the issue is resolved and monitor for any reoccurrence of the check engine light.