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

Solution

1. Preparation

• Gather required tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal for safety.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Using an O2 sensor socket, remove the upstream sensor first, followed by the downstream sensor.
  4. Install the new oxygen sensors, tightening to the manufacturer's recommended torque specifications (usually around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Remove the exhaust components leading to the catalytic converter, if necessary, using a socket set (check for any bolts that may require special handling).
  2. Support the catalytic converter as you detach it to prevent it from falling.
  3. Inspect the catalytic converter for any signs of blockage or damage.
  4. Install the new catalytic converter in reverse order of removal, ensuring proper alignment and torque specifications for the bolts (typically 30-40 ft-lbs).
  5. Reconnect any exhaust components and ensure all seals are secure.

4. Reset the Engine Control Module (ECM)

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM memory.