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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Exhaust System

• Sub-steps:
  • Lift the vehicle using a jack and secure with jack stands.
  • Visually inspect the entire exhaust system for any visible damage or leaks.
  • If leaks are found, repair or replace damaged sections of exhaust piping.

3. Test and Replace Oxygen Sensors

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors.
  • Disconnect the electrical connectors and remove the sensors using an oxygen sensor socket.
  • Test the sensors with a multimeter to check their resistance and voltage output.
  • If faulty, replace with new OEM or quality aftermarket sensors. Torque to manufacturer specifications (typically around 33 lb-ft for most sensors).

4. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  • If the catalytic converter is damaged or contaminated, remove it by unbolting it from the exhaust manifold and the exhaust pipe.
  • Install a new catalytic converter, ensuring proper alignment and sealing.
  • Torque bolts to manufacturer specifications (refer to service manual for specific torque settings).

5. Reassemble and Reconnect

• Sub-steps:
  • Reconnect any components that were removed during the repair.
  • Reconnect the battery terminals.
  • Start the engine and allow it to reach operating temperature.