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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

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 to carefully unscrew and remove each oxygen sensor.
3. Inspect the wiring: Check the wiring harness for any frays or disconnections.
4. Install new sensors: Apply anti-seize compound on the threads of new oxygen sensors, then install them securely.
   • Torque specification: Tighten to manufacturer specifications (typically around 30 lb-ft).
5. Reconnect the battery: Reattach the negative battery terminal.

3. Replace the Catalytic Converter (if necessary)

1. Remove the exhaust components: Unbolt the exhaust pipes connected to the catalytic converter using a socket set.
2. Take out the old catalytic converter: Carefully remove the catalytic converter from its mounting.
3. Install the new catalytic converter: Position the new catalytic converter in place and secure it with bolts.
   • Torque specification: Tighten to manufacturer specifications (specific torque values may vary).
4. Reconnect exhaust pipes: Ensure all flanges are sealed properly and reattach any necessary hangers.

4. Clear Codes and Test Drive

1. Clear the fault codes: Use the OBD-II scanner to erase the P0420 code from the vehicle's memory.
2. Test drive the vehicle: Drive the vehicle for at least 20-30 minutes under various conditions to ensure the issue is resolved and check that the check engine light does not reappear.