how to fix P0420 code in Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface and the engine is cool.
• Gather necessary tools and parts.
• Disconnect the battery before starting any repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream sensor first; disconnect the wiring harness.
  3. Install the new upstream O2 sensor and torque to the manufacturer's specifications (typically around 30 lb-ft).
  4. Repeat for the downstream O2 sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Wrench set, cutting torch or exhaust saw, gasket scraper
• Sub-steps:
  1. Remove any exhaust heat shields or components obstructing access to the catalytic converter.
  2. Cut the old catalytic converter from the exhaust system using a cutting torch or exhaust saw.
  3. Clean the mating surfaces on the exhaust pipes with a gasket scraper to ensure a proper seal.
  4. Install the new catalytic converter, ensuring it is oriented correctly, and secure it with the appropriate hardware.
  5. Reattach any heat shields and components removed during the process.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code and any other related codes.