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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Raise the vehicle securely using jack stands if accessing the exhaust system underneath.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, wrench set, penetrating oil.
• Remove the upstream O2 sensor:
  1. Apply penetrating oil to the O2 sensor threads to ease removal.
  2. Use the O2 sensor socket to unscrew and remove the sensor.
  3. Install the new O2 sensor and tighten it to the manufacturer's specifications (typically around 30 lb-ft).
• Repeat the process for the downstream O2 sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Remove the catalytic converter:
  1. Unbolt the flanges connecting the catalytic converter to the exhaust pipes.
  2. Remove any hangers securing the catalytic converter using a pry bar if necessary.
  3. Replace with a new catalytic converter, ensuring the exhaust gaskets are in good condition.
  4. Torque the bolts to manufacturer's specifications (usually around 25 lb-ft).

4. Clear the 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.