how to fix P0420 code in Ford Explorer Sixth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts necessary for the repair.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the battery negative terminal to ensure safety.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil
• Inspect the upstream and downstream oxygen sensors for damage.
• If damaged, replace the oxygen sensors:
  • Apply penetrating oil to the sensor threads and allow it to soak.
  • Disconnect the wiring harness connector from the sensor.
  • Use the O2 sensor socket to unscrew the sensor from the exhaust.
  • Install the new sensor, ensuring it is properly torqued (typically around 30 ft-lbs).
  • Reconnect the wiring harness.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary), gasket scraper
• If the catalytic converter is faulty:
  • Disconnect the exhaust pipes from the catalytic converter, noting the configuration.
  • Remove any clamps or bolts securing the catalytic converter; use an exhaust pipe cutter if necessary.
  • Clean the mating surfaces of the exhaust pipes and the engine to ensure a proper seal.
  • Install the new catalytic converter, tightening the bolts to manufacturer specifications (typically around 40 ft-lbs).
  • Reconnect any exhaust piping and clamps.

4. Reset the Engine Control Module (ECM)

• Reconnect the battery negative terminal.
• Use the OBD-II scanner to clear the P0420 code and reset the ECM.