how to fix the check engine light code P0420 on Ford Explorer Sixth Generation (2020-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, jack and jack stands, exhaust pressure gauge, multimeter.
• Clear the P0420 code using the OBD-II scanner.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors near the catalytic converter.
  2. Disconnect the battery to avoid electrical shorts.
  3. Use a socket wrench to remove the oxygen sensors from the exhaust system.
  4. Inspect the old sensors for damage or contamination; replace if necessary.
  5. Install new oxygen sensors, ensuring they are properly torqued to the manufacturer’s specifications (typically around 30-40 lb-ft).
  6. Reconnect the battery.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Safely lift the vehicle using a jack and secure with jack stands.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Use a socket set to detach the catalytic converter from the exhaust system.
  4. Inspect the old catalytic converter for signs of damage or clogging; if faulty, replace it with a new unit.
  5. Install the new catalytic converter, ensuring proper alignment and tightness of bolts (torque to manufacturer specifications).
  6. Reattach any heat shields or brackets removed earlier.

4. Final Checks

• Sub-steps:
  1. Start the engine and allow it to reach operating temperature.
  2. Use the OBD-II scanner to clear any existing codes and check for new codes.
  3. Monitor the vehicle for any unusual noises or exhaust leaks.