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

Solution

1. Preparation

• Gather necessary tools and parts for the repair.
• Disconnect the vehicle battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use an O2 sensor socket to carefully remove the sensors from the exhaust manifold and exhaust pipe respectively.
  3. Inspect the wiring harness and connectors for damage or corrosion; replace if necessary.
  4. Install new oxygen sensors by reversing the removal steps, ensuring they are torqued to manufacturer specifications (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Remove the exhaust heat shield if necessary to access the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust manifold and exhaust system using a socket set, and carefully remove it from the vehicle.
  3. Inspect the old catalytic converter for signs of damage or clogging; a rattling sound indicates internal damage.
  4. Install the new catalytic converter, ensuring proper alignment and sealing. Torque bolts to manufacturer specifications.

4. System Reset and Recheck

• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use an OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and allow it to reach operating temperature.