how to fix P0420 code on Ford Explorer Sixth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate Sensors: Find the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove Sensors:
   • Use an oxygen sensor socket or wrench.
   • Carefully disconnect the electrical connectors.
3. Install New Sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Screw in the sensors by hand and then tighten to manufacturer's specifications (usually around 30 lb-ft).
   • Reconnect the electrical connectors.

3. Check and Replace Catalytic Converter (if necessary)

1. Temperature Test: Confirm the catalytic converter is inefficient by measuring the temperature difference between the inlet and outlet. A difference of less than 100°F indicates a failing converter.
2. Remove Old Converter:
   • Support the exhaust system with a jack stand.
   • Remove any bolts or clamps securing the catalytic converter to the exhaust pipes using a socket set.
   • Gently lower and remove the old catalytic converter.
3. Install New Converter:
   • Position the new catalytic converter and secure it with bolts or clamps.
   • Ensure all connections are tight and leak-free.

4. Reset the ECU

1. Reconnect Battery: Reconnect the battery terminal.
2. Clear Codes: Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Recheck Systems: Start the engine and allow it to reach operating temperature.

Tools Required:

• OBD-II scanner
• Oxygen sensor socket
• Socket set
• Torque wrench
• Infrared thermometer
• Jack and jack stands

Parts Required:

• Upstream and downstream oxygen sensors (if faulty)
• New catalytic converter (if damaged)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Ensure the engine is cool before working on the exhaust system.
• Use personal protective equipment (gloves, goggles) when handling exhaust components.