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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical issues.
• Allow the vehicle to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, ratchet, and wrench
• If the oxygen sensor readings are outside the normal range:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use the O2 sensor socket to remove the faulty sensor(s).
  3. Apply anti-seize compound to the threads of the new sensor.
  4. Install the new oxygen sensor(s) and torque to manufacturer specifications (typically around 30 Nm / 22 lb-ft).

3. Inspect and Replace the Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)
• If the catalytic converter is damaged or restricted:
  1. Remove the exhaust components connected to the catalytic converter, noting any gaskets or seals that may need replacement.
  2. Cut the old catalytic converter out if it is welded in place.
  3. Install the new catalytic converter using new gaskets and bolts, torquing to the manufacturer’s specifications.
  4. Reattach any exhaust components and ensure all connections are secure.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• After repairs:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Test drive the vehicle to verify that the check engine light does not reappear.