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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench, multimeter.
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Disconnect the electrical connector.
  2. Use the O2 sensor socket to unscrew the sensor from the exhaust manifold.
  3. Install the new sensor, hand-tighten, then torque to manufacturer's specifications (typically around 30 lb-ft).
  4. Reconnect the electrical connector.
• Repeat the process for the downstream (post-catalytic) oxygen sensor if testing indicates it is faulty.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if applicable).
• If the catalytic converter is damaged:
  1. Disconnect any exhaust pipes attached to the converter.
  2. Remove any brackets or hangers securing the converter.
  3. Cut the exhaust pipes if necessary, and remove the old catalytic converter.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reattach exhaust pipes and secure all connections, torquing them to specifications.

4. Reset the OBD-II System

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the system.