how to fix P0420 code on Ford F-150 Fourteenth Generation (2021-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Raise the vehicle securely using jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the wiring and connectors for damage.
• If the sensors are faulty, install new ones:
  • Apply anti-seize lubricant to the threads of the new O2 sensors.
  • Torque the sensors to the manufacturer’s specification (typically around 30-40 lb-ft).

3. Check and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter or saw, gasket scraper.
• Remove the exhaust pipes connected to the catalytic converter:
  • Cut or unbolt any connections as necessary.
  • Remove the catalytic converter from its mounts.
• Inspect the old catalytic converter for blockages or damage.
• Install the new catalytic converter:
  • Position the new converter and align it with the exhaust system.
  • Tighten all bolts to the manufacturer’s specifications (check service manual for torque values).

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to ensure the check engine light does not reappear.