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

Solution

1. Preparation

• Gather necessary tools and parts. Ensure the vehicle is parked on a level surface and the engine is cool.
• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, jack and jack stands, safety goggles, gloves.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Disconnect the negative battery terminal to prevent electrical shorts.
  2. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  3. Use a socket wrench to unscrew and remove the faulty oxygen sensors.
  4. Install new oxygen sensors, ensuring the connectors are secured.
  5. Reconnect the negative battery terminal.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Raise the vehicle using a jack and secure with jack stands.
  2. Locate the catalytic converter in the exhaust system.
  3. Use a socket set to remove the bolts securing the catalytic converter.
  4. Inspect the mounting surfaces for cracks or damage.
  5. Install the new catalytic converter, ensuring to torque the bolts to the manufacturer's specifications (typically around 30-40 lb-ft).
  6. Reconnect any exhaust hangers and ensure a secure fit.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  2. Start the engine and allow it to warm up.
  3. Perform a test drive for at least 20 minutes under varying conditions to ensure the repair was successful.