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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Unplug the connectors and inspect for corrosion or damage.
  3. Use a multimeter to test the voltage output of the upstream sensor (should fluctuate between 0.1 to 0.9 volts) and the downstream sensor (should have a steady voltage around 0.5 volts).
  4. Replace any faulty oxygen sensors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Safely lift the vehicle using jack stands.
  2. Remove the heat shield covering the catalytic converter (if applicable).
  3. Unbolt the catalytic converter from the exhaust system using the appropriate socket set.
  4. Inspect the old catalytic converter for signs of clogging or physical damage.
  5. Install the new catalytic converter, ensuring proper alignment.
  6. Torque the bolts to the manufacturer specifications (typically around 30-45 lb-ft, but verify with service manual).

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the vehicle and allow it to reach operating temperature.