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

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the battery to ensure safety while working on electrical components.
• Raise the vehicle safely using jack stands if necessary.

2. Inspect and Repair Exhaust System

• Inspect for Leaks:
  • Visually check the entire exhaust system for leaks or damage.
  • Use soap and water solution on suspected areas to find leaks.
• Repair or Replace:
  • If any leaks are found, repair them using exhaust tape or replace damaged sections.

3. Inspect and Test Oxygen Sensors

• Remove Oxygen Sensors:
  • Use an O2 sensor socket to remove the upstream and downstream oxygen sensors.
• Test Sensors:
  • Use a multimeter to check the voltage output of both sensors. The upstream sensor should fluctuate between 0.1 to 0.9 volts, while the downstream sensor should have a more stable reading.
  • Replace any faulty sensors.

4. Inspect and Replace Catalytic Converter (if needed)

• Check for Clogging:
  • Use a pressure gauge to measure backpressure in the exhaust system. A reading above 3 psi at idle indicates a clogged converter.
• Replace Converter:
  • If clogged, remove the old catalytic converter using a socket set.
  • Install a new catalytic converter using the manufacturer's specified torque values for the bolts.

5. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Conduct a road test to ensure the vehicle operates normally and the check engine light does not return.