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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is parked on a level surface and securely supported on jack stands.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, torque wrench.

• Remove the upstream (pre-catalytic) O2 sensor:

  1. Locate the O2 sensor on the exhaust manifold or downpipe.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Install the new O2 sensor and torque to manufacturer specifications (typically around 30 lb-ft).

• Repeat for the downstream (post-catalytic) O2 sensor if needed.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, cutting tools (if necessary), exhaust pipe clamps.
• Check for any physical damage or clogging in the catalytic converter:
  1. Remove the exhaust pipe connected to the catalytic converter.
  2. Inspect the converter for signs of clogging (e.g., discoloration, rattling).
  3. If defective, remove the old catalytic converter.
  4. Install the new catalytic converter, ensuring all gaskets are replaced and connections are secure. Torque bolts to manufacturer specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative terminal of the battery.
• Use the OBD-II scanner to clear any stored trouble codes.
• Start the engine and allow it to reach operating temperature.