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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the ignition is turned off.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack stands, exhaust pipe cutter (if necessary).
• Safety Warnings: Disconnect the battery before working on electrical systems and allow the exhaust system to cool before starting work.

2. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the electrical connectors from the sensors.
  3. Use the appropriate socket to remove the sensors from the exhaust system.
  4. Install the new sensors, ensuring they are tightened to the manufacturer's specification (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Support the vehicle on jack stands and remove the undercarriage shield if present.
  2. Disconnect the exhaust pipes from the catalytic converter using an exhaust pipe cutter or a wrench.
  3. Remove any mounting bolts or brackets securing the catalytic converter.
  4. Carefully remove the old catalytic converter from the vehicle.
  5. Install the new catalytic converter, ensuring proper alignment.
  6. Reattach exhaust pipes and secure all connections with bolts, tightening them to the manufacturer's specification.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to see if the check engine light reappears.