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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on the electrical systems.
• Allow the engine to cool completely before beginning work.

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. Remove the Sensors: Use an oxygen sensor socket or wrench to carefully unscrew the sensors from their mounting locations.
3. Inspect the Sensors: Examine the sensors for any damage or excessive carbon buildup.
4. Install New Sensors: If replacement is needed, apply anti-seize compound on the threads of the new sensors and screw them into place, tightening to manufacturer specifications (usually around 30 Nm or 22 lb-ft).
5. Reconnect the Electrical Connectors: Ensure the connectors for both sensors are securely fastened.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check for Damage: Inspect the catalytic converter for any signs of physical damage or rattling noises when shaken.
2. Remove the Old Converter: Disconnect the exhaust pipes from both ends of the catalytic converter using a socket set. If necessary, cut the pipes if they are rusted.
3. Install New Converter: Position the new catalytic converter and secure it with the appropriate hardware. Tighten bolts to manufacturer specifications.
4. Reconnect Exhaust System: Reinstall the exhaust pipes, ensuring a tight fit to prevent leaks.

4. Reset the Engine Control Module (ECM)

1. Reconnect the Battery: Once repairs are completed, reconnect the battery terminals.
2. Clear the Codes: Use the OBD-II scanner to clear the P0420 code from the ECM.