how to fix P0420 code in Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the threads and connectors of the sensors for damage or corrosion.
• Install the new oxygen sensors, tightening them to the manufacturer's specified torque (typically around 30 ft-lbs).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Remove the exhaust pipes connected to the catalytic converter by loosening the clamps and bolts.
• Use the exhaust hanger removal tool to detach the catalytic converter from its mounts.
• Inspect the catalytic converter for blockages or physical damage.
• Install the new catalytic converter, ensuring it is properly aligned.
• Reattach the exhaust pipes and tighten all connections to the specified torque.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Perform a test drive to ensure the vehicle operates smoothly and the check engine light does not reappear.