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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor located before the catalytic converter:
  • Use the O2 sensor socket to unscrew the sensor.
  • Inspect the sensor for damage or contamination.
  • If faulty, install the new oxygen sensor and torque it to the manufacturer's specification (typically around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor located after the catalytic converter.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Raise the vehicle safely using jack stands.
• Unbolt the catalytic converter from the exhaust system:
  • Use a socket set to remove mounting bolts.
  • Carefully detach the converter and inspect for damage.
• If replacement is needed, install the new catalytic converter:
  • Ensure a new exhaust gasket is in place.
  • Bolt the new converter securely and torque to manufacturer specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.