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

Solution

1. Preparation

• Gather required tools and parts.
• Ensure the vehicle is parked on a level surface and securely raise it using jack stands.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Repair Exhaust System

• Tools Required: Socket set, wrench set, exhaust pipe cutter (if needed)
  • Inspect all exhaust joints and connections for leaks. Tighten any loose clamps or bolts.
  • If leaks are found, replace gaskets or clamps as required. Use high-temperature exhaust sealant if necessary.

3. Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
  • Connect the OBD-II scanner to the vehicle and monitor the live data for the upstream and downstream oxygen sensors.
  • If either sensor is not functioning within normal parameters, replace the faulty sensor. Follow these sub-steps:
    • Disconnect the electrical connector from the faulty sensor.
    • Use the appropriate wrench to unscrew the sensor from its mounting location.
    • Install the new sensor and reconnect the electrical connector. Ensure it is secure.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, oxygen sensor socket, ratchet, torque wrench
  • If diagnostic tests indicate a faulty catalytic converter, proceed to replace it:
    • Remove the oxygen sensors from the catalytic converter using the oxygen sensor socket.
    • Unscrew the catalytic converter from the exhaust system (typically held by bolts or flanges).
    • Install the new catalytic converter by reversing the removal steps. Ensure all bolts are torqued to the manufacturer's specifications.
    • Reinstall the oxygen sensors into the new catalytic converter.

5. Reset the Engine Control Module

• Tools Required: OBD-II scanner
  • Reconnect the battery and use the OBD-II scanner to clear the P0420 code from the ECM memory.