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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter.
• Remove the oxygen sensor from the exhaust system before the catalytic converter.
  • Sub-steps:
    1. Disconnect the electrical connector.
    2. Use the O2 sensor socket to unscrew the sensor.
    3. Install the new oxygen sensor and torque to manufacturer specifications (usually around 30 ft-lbs).
    4. Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, gasket scraper.
• Remove the catalytic converter if inspection shows it is damaged or clogged.
  • Sub-steps:
    1. Remove any exhaust hangers to free the converter.
    2. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
    3. Clean the mounting surfaces to ensure a proper seal for the new converter.
    4. Install the new catalytic converter and torque bolts to manufacturer specifications (typically around 30-35 ft-lbs).
    5. Reinstall exhaust hangers.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Clear the P0420 code from the ECM.
  • Sub-steps:
    1. Connect the OBD-II scanner to the vehicle's diagnostic port.
    2. Follow the scanner instructions to clear the trouble codes.
    3. Disconnect the scanner when finished.