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

Solution

1. Preparation

• Gather tools and parts needed.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor:
  • Locate the sensor, usually near the exhaust manifold.
  • Use the O2 sensor socket to unscrew it from the exhaust pipe.
  • Inspect the sensor for any physical damage.
• Replace with a new oxygen sensor if faulty.
• Reinstall and torque to manufacturer specifications (typically around 30-40 lb-ft).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter, gasket scraper
• Visually inspect the catalytic converter for damage or signs of clogging.
• If replacement is necessary:
  • Remove the exhaust bolts securing the catalytic converter to the exhaust pipe.
  • Cut the exhaust pipe if necessary for removal.
  • Clean the exhaust flanges with a gasket scraper to ensure a proper seal.
  • Install the new catalytic converter and secure it with bolts, torquing to manufacturer specifications (typically around 25-30 lb-ft).

4. Reassemble and Reconnect Battery

• Reconnect any components that were removed or disconnected during the process.
• Reconnect the battery terminal securely.