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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shocks.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter, safety glasses, gloves.
• Locate the upstream and downstream oxygen sensors on the exhaust system.
• Using the O2 sensor socket, remove the upstream oxygen sensor. Inspect the threads and the sensor for damage.
• Test the new oxygen sensor's resistance using a multimeter to ensure it is within specification.
• Install the new upstream oxygen sensor, tightening it to the manufacturer's specifications (usually around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor if it is also faulty.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed), replacement catalytic converter.
• Remove the exhaust pipes connected to the catalytic converter using a socket set. Note how they are connected for reinstallation.
• If the catalytic converter is damaged or blocked, replace it with a new one, ensuring it matches the vehicle's specifications.
• Install the new catalytic converter, tightening all connections to the manufacturer's torque specifications.
• Reattach the exhaust pipes and ensure all connections are secure.

4. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive under various driving conditions to monitor for any reoccurrence of the code.