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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the exhaust system to cool down.

2. Inspect and Clean Oxygen Sensors

1. Remove Oxygen Sensors:

   • Use a socket wrench to remove the upstream and downstream oxygen sensors.
   • Inspect wiring for any damage or corrosion.

2. Clean Sensors:

   • Use an oxygen sensor-safe cleaner to gently clean the sensor elements.
   • Allow to dry completely before reinstalling.

3. Inspect Catalytic Converter

1. Visual Inspection:
   • Check for any dents, rust, or signs of overheating on the catalytic converter.
2. Check Temperature:
   • Start the engine and use an infrared thermometer to measure inlet and outlet temperatures of the catalytic converter. A significant difference indicates a possible failure.

4. Replace Catalytic Converter (if necessary)

1. Remove Old Catalytic Converter:

   • Use a wrench to remove any bolts securing the catalytic converter to the exhaust system.
   • Carefully detach the converter from the exhaust pipes.

2. Install New Catalytic Converter:

   • Position the new catalytic converter and secure it with bolts.
   • Ensure all connections are tight and free of leaks.

5. Reinstall Oxygen Sensors

• Reinstall the cleaned or new oxygen sensors in their respective locations.
• Ensure they are securely tightened, but avoid over-tightening.

6. Reset Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to erase the P0420 code from the ECM.