how can I fix code P0420 in my Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down if the exhaust system has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor by disconnecting the wiring harness and using the O2 sensor socket.
• Install the new oxygen sensor, torqueing to the manufacturer's specifications (usually around 30 lb-ft).
• Repeat the procedure for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, jack stands, exhaust pipe cutter (if applicable).
• Remove any heat shields covering the catalytic converter.
• Disconnect the exhaust pipes at both ends of the catalytic converter using a socket set. If bolts are rusted, use penetrating oil.
• Carefully remove the catalytic converter and inspect it for internal damage or blockage.
• Install the new catalytic converter, ensuring all gaskets are replaced and connections are secure.
• Torque the exhaust bolts to manufacturer specifications.

4. Clear Codes and Test Drive

• Reconnect the battery terminal.
• 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 ensure the check engine light does not return.