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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Wear safety gloves and goggles.

2. Replace Faulty Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Sub-steps:
  1. Disconnect the vehicle battery to prevent electrical shorts.
  2. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  3. Unplug the electrical connectors from both oxygen sensors.
  4. Use the O2 sensor socket or a wrench to remove the sensors from the exhaust manifold and catalytic converter.
  5. Install the new oxygen sensors by screwing them into their respective locations and tightening to the manufacturer's specified torque (usually around 30-40 lb-ft).
  6. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if applicable), new catalytic converter
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Inspect the catalytic converter for any signs of damage or blockage.
  3. If replacement is necessary, use an exhaust pipe cutter to remove the old catalytic converter.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Tighten all bolts and connections to the specified torque.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and perform a test drive to ensure the check engine light remains off.