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

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the battery to prevent electrical shorts.
• Raise the vehicle using a jack and secure it with jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench, multimeter.
• Remove the pre-catalytic converter oxygen sensor:
  1. Unplug the electrical connector.
  2. Use the O2 sensor socket to remove the sensor from the exhaust manifold.
• Install the new oxygen sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Install the new sensor and tighten to the manufacturer's specifications (usually around 30 ft-lbs).
  3. Reconnect the electrical connector.
• Repeat the process for the post-catalytic converter oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, gaskets.
• Remove the catalytic converter:
  1. Disconnect the exhaust pipes connected to the catalytic converter using a socket set.
  2. Remove any mounting bolts or brackets securing the catalytic converter.
  3. Take out the old catalytic converter.
• Install the new catalytic converter:
  1. Position the new converter in place and secure it with the mounting bolts.
  2. Use new gaskets to prevent exhaust leaks.
  3. Torque the bolts to the manufacturer's specifications (typically around 25-30 ft-lbs).

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Perform a test drive to ensure the engine runs smoothly and the check engine light does not reappear.