how to fix P0420 code on Ford Explorer Sixth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical issues during repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Apply penetrating oil to the sensor threads and allow it to soak.
  3. Remove the upstream O2 sensor using the O2 sensor socket.
  4. Install the new upstream O2 sensor and torque it to the manufacturer's specification (usually around 30 lb-ft).
  5. Repeat the process for the downstream O2 sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, torque wrench.
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Disconnect the exhaust pipes from the catalytic converter by removing bolts or clamps.
  3. Remove any heat shields covering the catalytic converter if applicable.
  4. Remove the catalytic converter from its mounts.
  5. Install the new catalytic converter, ensuring it is aligned properly and securely bolted.
  6. Reconnect the exhaust pipes and heat shields, torquing them to specifications.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive, ensuring to monitor performance and check for the reappearance of the check engine light.