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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands, safety goggles, gloves.
• Disconnect the vehicle's battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use a socket wrench to remove the oxygen sensors from the exhaust system.
  3. Inspect the sensors for any signs of damage or contamination.
  4. If damaged, replace the sensors with OEM or high-quality aftermarket parts.
  5. Reinstall the sensors and torque them to the manufacturer's specifications (typically around 30 lb-ft).

3. Examine the Catalytic Converter

• Sub-steps:
  1. Visually inspect the catalytic converter for dents, cracks, or signs of overheating.
  2. If any damage is found, remove the catalytic converter by loosening the bolts that secure it to the exhaust system.
  3. Replace with a new catalytic converter, ensuring that it meets OEM specifications.
  4. Reinstall the catalytic converter and torque the bolts to the recommended specifications.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use the OBD-II scanner to clear any stored codes.
  3. Start the vehicle and allow it to reach operating temperature.
  4. Perform a test drive under various conditions (city and highway) to ensure the issue is resolved.