how to resolve 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 battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the upstream oxygen sensor using a wrench.
  • Sub-step: Use the multimeter to test the sensor's resistance. Replace if it is out of manufacturer specifications.
• Reinstall the upstream sensor and repeat for the downstream sensor.
  • Sub-step: If the downstream sensor shows a steady voltage rather than fluctuating, it may need replacement.

3. Inspect Catalytic Converter

• Tools Required: Socket set, torque wrench
• Visually inspect the catalytic converter for signs of damage or blockage.
  • Sub-step: If physical damage is present, proceed to remove the catalytic converter.
• Remove the catalytic converter from the exhaust system.
  • Sub-step: Use a torque wrench to ensure bolts are tightened to manufacturer specifications upon reinstallation of a new converter.

4. Replace Catalytic Converter (if necessary)

• Parts Required: New catalytic converter, new gaskets
• Install the new catalytic converter and ensure all connections are secure.
  • Sub-step: Replace any gaskets to prevent exhaust leaks.

5. Clear Error Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and reset the check engine light.