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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, safety glasses, gloves.
• Disconnect the battery to prevent any electrical shorts during repair.

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system for any leaks, focusing on joints and connections.
  2. If leaks are found, use exhaust sealant or replace damaged sections of the exhaust pipe.
  3. Re-tighten any loose clamps and connections.

3. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Using a socket wrench, carefully unscrew the faulty oxygen sensor from the exhaust pipe.
  3. Apply anti-seize compound to the threads of the new oxygen sensor.
  4. Install the new sensor and tighten it to the manufacturer's specifications (usually about 30 lb-ft).
  5. Reconnect the wiring harness to the new sensor.

4. Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields covering the catalytic converter using a socket set.
  2. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  3. Remove the catalytic converter from its mounting using a torque wrench to ensure proper reinstallation.
  4. Install the new catalytic converter and secure it to the exhaust system.
  5. Reinstall any heat shields removed earlier.

5. Reset the Engine Control Module (ECM)

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 trouble code from the ECM.
  3. Start the engine and allow it to reach operating temperature.