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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, infrared thermometer, jack and jack stands, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is turned off. Disconnect the battery to prevent electrical issues while working.

2. Inspect and Replace O2 Sensors (if faulty)

1. Locate the O2 Sensors:
   • The upstream O2 sensor is usually located before the catalytic converter, and the downstream O2 sensor is after it.
2. Remove the O2 Sensors:
   • Use a socket wrench to unscrew the sensors. Be careful not to damage the wiring.
3. Test the O2 Sensors:
   • Use a multimeter to check the voltage output. Replace any sensor that does not meet specifications.
4. Install New O2 Sensors:
   • Apply anti-seize compound to the threads and install the new sensors, tightening them to the manufacturer's specifications.

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

1. Remove the Exhaust Components:
   • Use a socket set to remove the bolts securing the catalytic converter in place. Support the exhaust system as needed.
2. Inspect the Catalytic Converter:
   • Look for any signs of physical damage or clogging. If damaged, proceed to replace it.
3. Install the New Catalytic Converter:
   • Position the new catalytic converter and secure it with bolts. Tighten to the specified torque settings.
4. Reinstall Exhaust Components:
   • Ensure all connections are secure and leak-free.

4. Clear Codes and Test Drive

1. Reconnect the Battery:
   • Ensure all connections are secure before reconnecting the battery.
2. Clear the P0420 Code:
   • Use the OBD-II scanner to clear the error codes.
3. Test Drive:
   • Drive the vehicle under various conditions to monitor for reoccurrence of the check engine light.