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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, infrared thermometer, socket set, jack and jack stands, safety glasses, gloves.
• Disconnect the battery negative terminal to ensure safety while working on electrical components.

2. Inspect and Clean Oxygen Sensors

• Remove the oxygen sensors from the exhaust system using the appropriate socket.
  • Tools Required: Oxygen sensor socket.
• Inspect the sensors for carbon buildup or damage.
• Clean the sensors with a suitable cleaner or replace them if necessary.

3. Replace Catalytic Converter (if necessary)

• Raise the vehicle using a jack and secure it with jack stands.
• Remove the exhaust components connected to the catalytic converter, starting from the manifold.
  • Sub-steps:
    • Unbolt the exhaust flange connections and any hangers.
    • Carefully slide the catalytic converter out of the exhaust system.
• Install the new catalytic converter.
  • Ensure proper alignment and secure it with new gaskets and bolts as necessary. Torque the bolts to the manufacturer’s specifications.
  • Torque Specification: Refer to the service manual for the specific torque value.

4. Reinstall Oxygen Sensors

• Reinstall the cleaned or new oxygen sensors back into their respective locations on the exhaust system.
• Reconnect the battery terminal.

5. Clear Error Codes

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