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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery for safety.
• Ensure the vehicle is on a level surface and use wheel chocks.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, wrench set
• Remove the upstream O2 sensor (before the catalytic converter).
  • Unplug the O2 sensor connector.
  • Use the O2 sensor socket to unscrew the sensor.
• Install the new O2 sensor.
  • Apply anti-seize compound to the threads of the new sensor.
  • Screw in the sensor and tighten to the manufacturer's specifications (usually around 30 ft-lbs).
• Repeat the process for the downstream O2 sensor if deemed necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed)
• Remove any components obstructing access to the catalytic converter (e.g., heat shields).
• Disconnect the exhaust pipes from the catalytic converter.
  • Use the exhaust pipe cutter if necessary.
• Remove the catalytic converter.
  • Unbolt the converter from the exhaust manifold and exhaust pipe.
• Install the new catalytic converter.
  • Ensure proper alignment and bolt it back in place with the specified torque (typically around 25-30 ft-lbs).
• Reconnect all exhaust components and any removed heat shields.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.