how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety glasses, gloves.
• Ensure the vehicle is in a safe and well-ventilated area.
• Disconnect the battery negative terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Remove the sensors using an O2 sensor socket or appropriate wrench.
  4. Install new oxygen sensors, applying anti-seize compound on the threads.
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter in the exhaust system.
  3. Remove any heat shields or mounting brackets obstructing access.
  4. Unbolt and remove the old catalytic converter from the exhaust pipes.
  5. Install the new catalytic converter, ensuring proper alignment.
  6. Torque the bolts to manufacturer specifications (typically around 30-40 ft-lbs).
  7. Reinstall any heat shields or brackets removed earlier.

4. Reconnect Battery and Clear Codes

• Reconnect the battery negative terminal.
• Use the OBD-II scanner to clear any stored codes from the ECM.