how to fix P0420 code on Ford F-150 13th Generation (2015-2020)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off and cool.
• Disconnect the battery negative terminal for safety.

2. Inspect Exhaust System

• Tools Required: Visual inspection tools (flashlight), socket set.
• Inspect the exhaust pipes, gaskets, and joints for any signs of leaks or damage.
• Repair or replace any defective components as necessary.

3. Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor by disconnecting the harness and using the O2 sensor socket.
• Install the new oxygen sensor and tighten to manufacturer specifications (typically around 30 lb-ft).
• Repeat the process for the downstream (post-catalytic) oxygen sensor if it is also faulty.

4. Replace Catalytic Converter (if necessary)

• Parts Required: New catalytic converter.
• Tools Required: Socket set, jack stands, exhaust pipe cutter (if necessary).
• Raise the vehicle using jack stands and remove the bolts securing the catalytic converter to the exhaust system.
• Carefully remove the old catalytic converter and install the new one, ensuring proper alignment.
• Reattach all bolts and connections securely according to manufacturer specifications.

5. 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 to ensure the issue is resolved and the check engine light does not reappear.