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

Solution

1. Preparation

• Gather all tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and secure it with wheel chocks.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the downstream oxygen sensor (post-catalytic) first:
  1. Locate the sensor in the exhaust system after the catalytic converter.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Install the new sensor and torque to the manufacturer’s specifications (typically around 30-40 ft-lbs).
• Repeat for the upstream oxygen sensor (pre-catalytic) if necessary.

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

• Tools Required: Jack and jack stands, socket set, exhaust pipe cutter (if needed), gasket scraper, torque wrench.
• Remove the catalytic converter:
  1. Loosen the bolts connecting the catalytic converter to the exhaust system using a socket set.
  2. If the converter is rusted or welded, use an exhaust pipe cutter to remove it.
  3. Clean the mating surfaces on the exhaust system and ensure no debris remains.
• Install the new catalytic converter:
  1. Position the new catalytic converter and align it with the exhaust system.
  2. Secure it with bolts, ensuring it’s tightened to manufacturer specifications.
  3. Replace any gaskets if necessary to prevent leaks.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 error code.
• Start the engine and allow it to reach operating temperature.