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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Remove the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  • Sub-steps:
    1. Locate the O2 sensors on the exhaust pipe.
    2. Use the O2 sensor socket to unscrew the sensors.
    3. Inspect the sensors for carbon buildup or damage.
    4. Replace with new sensors if necessary (ensure the new sensors are compatible with the vehicle).
    5. Torque the new sensors to the manufacturer's specifications (usually around 30 lb-ft).

3. Inspect Catalytic Converter

• Tools Required: Jack and jack stands, exhaust backpressure gauge.
• Check the catalytic converter for physical damage and test for backpressure.
  • Sub-steps:
    1. Raise the vehicle using a jack and secure it with jack stands.
    2. Visually inspect the catalytic converter for dents, rust, or holes.
    3. Insert the exhaust backpressure gauge into the exhaust pipe before the catalytic converter.
    4. Start the engine and check for backpressure; it should be below 1.5 psi at idle.
    5. If backpressure is above the specified range, the catalytic converter may need replacement.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, sawzall or exhaust cutter, gasket scraper.
• Remove and replace the catalytic converter if it is determined to be faulty.
  • Sub-steps:
    1. Disconnect the exhaust pipe from the catalytic converter using the wrench.
    2. Cut the old catalytic converter out of the exhaust system if it is welded in place.
    3. Clean the mating surfaces with a gasket scraper.
    4. Install the new catalytic converter, ensuring proper alignment.
    5. Reconnect the exhaust pipe and secure with new bolts and gaskets.
    6. Torque to manufacturer's specifications.

5. Reconnect Battery and Clear Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and other related codes.