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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Ensure the vehicle is on a level surface and secure it with wheel chocks.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the upstream sensor, followed by the downstream sensor.
  4. Install the new sensors, tightening them to manufacturer specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed), gasket scraper.
• Sub-steps:
  1. Remove any heat shields or brackets securing the catalytic converter.
  2. Disconnect the exhaust pipes at both the inlet and outlet of the catalytic converter.
  3. If applicable, cut the exhaust pipes with an exhaust pipe cutter to remove the old catalytic converter.
  4. Clean the mating surfaces on the exhaust pipes using a gasket scraper to ensure a proper seal.
  5. Install the new catalytic converter, ensuring it is aligned correctly.
  6. Reattach exhaust pipes and secure them with bolts, tightening to the specified torque.

4. Clear Error Codes and Reconnect Battery

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the ECM.