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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and safely supported.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, multimeter, ratchet, torque wrench
• Remove the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors using the O2 sensor socket.
• Inspect the connectors for damage; replace if necessary.
• Install new oxygen sensors, ensuring to torque them to the manufacturer's specifications (typically around 33 lb-ft).
• Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if needed)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• If the catalytic converter is damaged or contaminated, locate the mounting bolts and exhaust hangers.
• Remove the exhaust hangers and bolts securing the catalytic converter to the exhaust system.
• Carefully remove the old catalytic converter and replace it with a new one, ensuring proper alignment.
• Torque the mounting bolts to the manufacturer's specifications (typically around 40 lb-ft).
• Reinstall any exhaust hangers that were removed.

4. Clear Codes and Test Drive

• Reconnect the OBD-II scanner to clear the P0420 code from the system.
• Test drive the vehicle under various conditions to ensure the check engine light does not reappear.