how to fix P0420 code on Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather tools and parts required for repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Apply penetrating oil to the threads of the oxygen sensors to ease removal.
  3. Use the O2 sensor socket to remove the upstream sensor first, followed by the downstream sensor.
  4. Install the new oxygen sensors and torque to the manufacturer’s specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary), gasket sealant
• Sub-steps:
  1. Raise the vehicle securely using jack stands.
  2. Remove any heat shields or components obstructing access to the catalytic converter.
  3. Disconnect the exhaust pipe from the catalytic converter using the socket set or exhaust pipe cutter if needed.
  4. Remove the old catalytic converter from the vehicle.
  5. Install the new catalytic converter, ensuring the gaskets are in place and secure.
  6. Reconnect the exhaust system and torque all connections to specifications.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECU.
  3. Test drive the vehicle for at least 20 minutes under various driving conditions to ensure no codes reappear.