how to fix P0420 code on Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety.
• Allow the vehicle to cool down before starting work.

2. Inspect and Repair Exhaust Leaks

• Tools Required: Socket set, exhaust pipe clamp tool.
• Instructions:
  1. Raise the vehicle using jack stands for access to the exhaust system.
  2. Visually inspect all exhaust joints and connections for leaks.
  3. Tighten any loose bolts or clamps.
  4. Replace any damaged gaskets or seals.

3. Replace Faulty Oxygen Sensors (if applicable)

• Tools Required: O2 sensor socket wrench.
• Instructions:
  1. Locate the upstream (before catalytic converter) and downstream (after catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use the O2 sensor socket wrench to unscrew the sensors from the exhaust pipe.
  4. Install the new sensors by threading them into the exhaust pipe and tightening to the manufacturer's specified torque.
  5. Reconnect the electrical connectors.

4. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, exhaust pipe clamp tool, torque wrench.
• Instructions:
  1. Disconnect the exhaust pipes connected to the catalytic converter using the socket set.
  2. Remove any brackets or supports holding the catalytic converter in place.
  3. Install the new catalytic converter and secure it with the existing bolts or new hardware if necessary.
  4. Torque the bolts to the manufacturer's specifications.

5. Reset the OBD-II System

• Tools Required: OBD-II scanner.
• Instructions:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the vehicle and allow it to reach operating temperature.