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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down completely before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Use an oxygen sensor socket and ratchet to unscrew the sensor.
   • Disconnect the electrical connector from the sensor.

2. Install the new upstream oxygen sensor:

   • Apply anti-seize compound to the threads of the new sensor.
   • Screw it into place and tighten to the manufacturer’s specified torque (typically around 30 ft-lbs).
   • Reconnect the electrical connector.

3. Repeat the above steps for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

1. Remove the catalytic converter:

   • Use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
   • Disconnect any hangers or brackets holding it in place.

2. Install the new catalytic converter:

   • Position the new converter in place and secure it using the original bolts, tightening them to the manufacturer’s specified torque.
   • Reinstall any hangers or brackets as necessary.

4. Clear Codes and Test

1. Reconnect the battery terminal.
2. Use the OBD-II scanner to clear the P0420 code.
3. Start the engine and allow it to reach normal operating temperature.
4. Perform a test drive to ensure that the check engine light does not reappear.