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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Remove the oxygen sensors:
  • Use an O2 sensor socket to remove the pre-catalytic and post-catalytic oxygen sensors.
  • Disconnect the wiring harness from each sensor.
• Install new oxygen sensors:
  • Apply anti-seize compound to the threads of the new sensors.
  • Install the new sensors and reconnect the wiring harness.
  • Torque the sensors to manufacturer specifications (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Remove the old catalytic converter:
  • Unbolt the exhaust pipes connected to the catalytic converter using a socket set.
  • If applicable, remove any mounting brackets or heat shields.
• Install the new catalytic converter:
  • Position the new catalytic converter in place.
  • Reattach the exhaust pipes and torque bolts to manufacturer specifications (typically around 25-30 ft-lbs).
  • Reinstall mounting brackets and heat shields as necessary.

4. Clear Codes and Test Drive

• Reconnect the battery:
  • Reconnect the negative battery terminal.
• Clear the P0420 code:
  • Use the OBD-II scanner to clear the stored trouble codes.
• Test drive the vehicle:
  • Drive the vehicle for at least 20-30 minutes to allow the system to complete readiness monitors.