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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Raise the vehicle and secure it on jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set
  • Locate the upstream and downstream oxygen sensors connected to the exhaust system.
  • Disconnect the electrical connectors from the sensors.
  • Use the O2 sensor socket to remove the sensors from the exhaust manifold (upstream) and catalytic converter (downstream).
  • Install the new oxygen sensors by threading them into the exhaust system and tightening them to the manufacturer’s specified torque (usually around 30 ft-lbs).
  • Reconnect the electrical connectors to the sensors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), exhaust gaskets
  • If the catalytic converter is damaged or clogged, remove the exhaust pipes leading to and from the catalytic converter.
  • If necessary, use a cutting tool to remove the old catalytic converter from the exhaust system.
  • Install the new catalytic converter, ensuring the inlet and outlet flanges are aligned properly.
  • Use new exhaust gaskets and torque bolts to the manufacturer's specifications (typically around 20-25 ft-lbs).
  • Reattach any exhaust pipes and ensure all connections are secure.

4. Reset the ECU

• Reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0420 code from the ECU.