how to fix P0420 code on Honda Pilot YF4 (2023-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 battery to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

• 2.1. Remove the upstream oxygen sensor:

  • Use an oxygen sensor socket to unscrew the sensor from the exhaust manifold.
  • Disconnect the electrical connector.

• 2.2. Install the new upstream oxygen sensor:

  • Thread the new sensor into the exhaust manifold and tighten to the manufacturer’s torque specifications (usually around 30 lb-ft, check specifics).
  • Reconnect the electrical connector.

• 2.3. Repeat for the downstream oxygen sensor if necessary:

  • Follow the same steps as above for the downstream sensor.

3. Inspect and Replace the Catalytic Converter

• 3.1. Remove the catalytic converter:

  • Using a socket set, unbolt the catalytic converter from the exhaust system.
  • Carefully lower the converter and inspect it for signs of damage or clogging.

• 3.2. Install the new catalytic converter:

  • Position the new catalytic converter in place.
  • Secure it with the bolts and ensure they are tightened to the manufacturer’s specifications.

4. Clear the Trouble Codes

• 4.1. Reconnect the battery.
• 4.2. Use the OBD-II scanner to clear the P0420 code.

5. Final Inspection

• 5.1. Start the engine and let it idle for a few minutes.
• 5.2. Check for any exhaust leaks around the new components.