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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery's negative terminal for safety.
• Raise the vehicle using a jack and securely place it on jack stands.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor from the exhaust manifold by turning it counterclockwise with the O2 sensor socket.
• Install the new oxygen sensor and tighten it to the manufacturer's specified torque (usually around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor if testing indicates it is faulty.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, torque wrench, exhaust gasket.
• Remove the heat shield (if applicable) by unscrewing the bolts.
• Disconnect the exhaust pipes from the catalytic converter, noting the gasket condition.
• Remove the catalytic converter by unbolting it from the exhaust manifold and the pipes.
• Install the new catalytic converter, ensuring to use a new gasket. Torque the bolts according to specifications (typically around 40-50 ft-lbs).
• Reinstall the heat shield.

4. Clear Codes and Test Drive

• Reconnect the battery's negative terminal.
• Use the OBD-II scanner to clear the P0420 code from the computer.
• Test drive the vehicle to ensure the check engine light does not return.