how to fix P0420 code on Ford F-150 12th Generation (2009-2014)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface.
• Wear safety gloves and goggles.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the Battery: Disconnect the negative battery terminal to prevent electrical shorts.
3. Remove the Old Sensors:
   • Use an oxygen sensor socket to unscrew the sensors from the exhaust system.
   • Disconnect the electrical connectors.
4. Install New Sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Screw the new sensors into place and connect the electrical connectors.
   • Tighten to manufacturer specifications (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Assess the Catalytic Converter: If both oxygen sensors are functioning correctly, and the issue persists, inspect the catalytic converter.
2. Remove the Exhaust Components:
   • Use a socket set to unbolt the exhaust pipes from the catalytic converter.
   • If equipped, remove any heat shields or brackets.
3. Replace the Catalytic Converter:
   • Install the new catalytic converter in the same position.
   • Reattach the exhaust pipes and tighten bolts to manufacturer specifications (check torque values).
4. Reinstall any removed components: Ensure heat shields and brackets are securely fastened.

4. Clear Codes and Test Drive

1. Reconnect the Battery: Connect the negative battery terminal.
2. Clear Error Codes: Use the OBD-II scanner to erase the P0420 code.
3. Test Drive: Drive the vehicle for at least 20 minutes to allow the engine to reach operating temperature and monitor for any reoccurring codes.