how to fix P0420 code on Ford F-150 12th Generation (2009-2014)

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface, engage the parking brake, and disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the wiring harness from both sensors.
  3. Use the O2 sensor socket to remove the old sensors by turning counterclockwise.
  4. Install new sensors, ensuring they are tightened to manufacturer specifications (usually around 30 lb-ft).
  5. Reconnect the wiring harness.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, penetrating oil, exhaust hanger removal tool.
• Sub-steps:
  1. Inspect the catalytic converter for physical damage or blockage.
  2. If replacement is needed, use penetrating oil to loosen the bolts connecting the catalytic converter to the exhaust system.
  3. Remove the exhaust hangers using the exhaust hanger removal tool.
  4. Remove the catalytic converter by unbolting it from the exhaust manifold and the pipe.
  5. Install the new catalytic converter, ensuring all bolts are tightened to specifications.
  6. Reinstall the exhaust hangers and check alignment.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the ECU.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to monitor for any reoccurring issues.