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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety goggles, gloves.
• Ensure the vehicle is parked on a level surface, and the engine is cool. Disconnect the battery's negative terminal.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Remove the electrical connectors from both sensors.
  3. Use a socket wrench to unscrew the sensors from the exhaust.
  4. Install new oxygen sensors by screwing them in place and reconnecting the electrical connectors.
  5. Torque the sensors to the manufacturer’s specifications (refer to service manual for exact value).

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust manifold bolts and any heat shields covering the catalytic converter.
  2. Disconnect the exhaust pipe from the catalytic converter.
  3. Remove the old catalytic converter by unbolting it from the exhaust system.
  4. Install the new catalytic converter, ensuring proper alignment of gaskets.
  5. Torque all bolts to the manufacturer’s specifications.

4. Clear the Error Code

• Sub-steps:
  1. Reconnect the battery's negative terminal.
  2. Use the OBD-II scanner to clear the P0420 error code.
  3. Start the vehicle and allow it to reach operating temperature.