how to fix the P0420 code on my Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet and extension, torque wrench.
• Sub-steps:
  • Remove the upstream oxygen sensor (usually located before the catalytic converter) by using the O2 sensor socket.
  • Install the new upstream oxygen sensor and tighten to manufacturer specifications (usually around 30 Nm).
  • Repeat the process for the downstream oxygen sensor (located after the catalytic converter).
  • Reconnect the battery terminal.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust cutter (if necessary).
• Sub-steps:
  • Disconnect the exhaust pipes from the catalytic converter, starting with any clamps or bolts.
  • Remove the catalytic converter from its mounting points.
  • Inspect the mounting gaskets; replace if they are worn or damaged.
  • Install the new catalytic converter and secure with bolts to the specified torque.
  • Reconnect the exhaust pipes and ensure all connections are tight.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  • Use the OBD-II scanner to clear the P0420 code.
  • Start the engine and allow it to reach operating temperature.
  • Take the vehicle for a test drive to monitor for any reoccurrence of the P0420 code.