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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and secure it with wheel chocks.
• Disconnect the battery before working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• 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 sensors from their respective exhaust pipe locations.
  4. Install the new oxygen sensors, tightening them to the manufacturer’s specified torque (usually around 30 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, high-temperature sealant.
• Sub-steps:
  1. Lift the vehicle using jack stands for access to the catalytic converter.
  2. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  3. If necessary, cut the exhaust pipes carefully to remove the old catalytic converter.
  4. Position the new catalytic converter in place and secure it with new gaskets or high-temperature sealant.
  5. Reconnect the exhaust system, ensuring all connections are secure and leak-free.

4. Clear Error Codes

• Use the OBD-II scanner to clear the P0420 code and any other stored error codes in the system.