how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, OBD-II scanner.
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Use the O2 sensor socket to carefully remove the upstream O2 sensor.
  3. Inspect the sensor for any signs of damage or carbon buildup. If faulty, replace with a new OEM or high-quality aftermarket sensor.
  4. Repeat the removal and inspection process for the downstream O2 sensor. Replace if necessary.
  5. Reconnect the electrical connectors to the new sensors.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter, clamps, gasket material.
• Sub-steps:
  1. Inspect the catalytic converter for any physical damage or rattling noise.
  2. If damaged, support the exhaust system and use the exhaust pipe cutter to remove the catalytic converter.
  3. Clean the mating surfaces on the exhaust pipe where the catalytic converter will attach.
  4. Install the new catalytic converter using new gaskets and clamps.
  5. Ensure all connections are tight and secure.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle’s battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Start the engine and let it idle for a few minutes.
  4. Take the vehicle for a test drive under various conditions (acceleration, deceleration, and idling).