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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface, and engage the parking brake.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the upstream sensor first, followed by the downstream sensor.
  4. Install the new sensors by threading them into their respective locations and tightening to manufacturer specifications (typically 30-35 ft-lbs).
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Sub-steps:
  1. Lift the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter and inspect it for physical damage or excessive carbon buildup.
  3. If replacement is needed, disconnect the exhaust pipes using a socket set. Cut the exhaust pipe if necessary for easier removal.
  4. Remove the old catalytic converter and install the new one, ensuring proper alignment.
  5. Tighten all bolts and clamps to manufacturer specifications (typically around 30-45 ft-lbs).

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery and start the engine.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Take the vehicle for a test drive to ensure the check engine light does not return and monitor for any abnormalities.