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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the vehicle battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and use jack stands for safety if working underneath.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using an O2 sensor socket, carefully remove the upstream sensor first.
   • Tools Required: O2 sensor socket, wrench.
3. Install the new upstream oxygen sensor; torque to manufacturer's specifications (typically around 30 lb-ft).
4. Repeat the process for the downstream oxygen sensor if indicated.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the heat shields from around the catalytic converter using a socket set.
2. Disconnect the exhaust pipes from the catalytic converter by removing the flange bolts.
   • Tools Required: Socket set, penetrating oil if bolts are rusted.
3. Remove any mounting brackets holding the catalytic converter in place.
4. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
5. Reattach all bolts and clamps, torque to specifications (generally around 30 lb-ft for flange bolts).
6. Reinstall the heat shields.

4. Clear Codes and Test

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code.
3. Start the engine and allow it to reach operating temperature.
4. Take the vehicle for a test drive to monitor for any reoccurrence of the check engine light.