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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream O2 sensor using the O2 sensor socket.
• Inspect the sensor for damage or contamination; replace if needed.
• Install the new O2 sensor, tightening it to the manufacturer’s specified torque (typically around 30 lb-ft).
• Repeat the process for the downstream O2 sensor if it shows signs of failure.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust hanger removal tool.
• Raise the vehicle using a jack and secure with jack stands.
• Remove the exhaust hangers to free the catalytic converter from the exhaust system.
• Unbolt the catalytic converter from the exhaust manifold and the pipe leading to the rear of the vehicle.
• Inspect the catalytic converter for internal damage (e.g., melted substrate), and replace if necessary.
• Install the new catalytic converter, ensuring all bolts are tightened to the manufacturer’s specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and clear any fault codes using the OBD-II scanner.
• Start the engine and let it idle for a few minutes, checking for any leaks or sounds.
• Take the vehicle for a test drive to ensure the engine runs smoothly and the check engine light does not return.