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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and engage the parking brake.
• Disconnect the battery to ensure safety during the repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the old upstream and downstream oxygen sensors using the O2 sensor socket.
• Install new oxygen sensors, ensuring they are tightened to the manufacturer's torque specifications (usually around 30-40 ft-lbs).
• Reconnect the battery.

3. Check and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary), gaskets
• Raise the vehicle and support it securely on jack stands.
• Disconnect the exhaust pipe from the catalytic converter. If necessary, use the exhaust pipe cutter to remove any rusted bolts.
• Remove the old catalytic converter, noting the position of any gaskets or brackets.
• Install the new catalytic converter, ensuring all gaskets are in place. Tighten all bolts to the manufacturer's specifications.
• Reconnect the exhaust pipe.

4. Clear Error Codes

• Use the OBD-II scanner to clear the P0420 error code from the vehicle's computer.
• Start the engine and allow it to reach operating temperature.

5. Perform a Test Drive

• Drive the vehicle under various conditions (city and highway) to ensure the repairs are effective.
• Monitor the performance and check for a reoccurrence of the check engine light.