how to fix P0420 code in Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Allow the exhaust system to cool before starting work.

2. Inspect and Replace Oxygen Sensors (if necessary)

• 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 wiring harness from each O2 sensor.
  3. Use the O2 sensor socket to remove the sensors.
  4. Install new O2 sensors, torque to manufacturer's specifications (typically around 30 ft-lbs).
  5. Reconnect the wiring harness.

3. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. If applicable, cut the exhaust pipe before and after the catalytic converter using an exhaust pipe cutter.
  3. Remove the old catalytic converter by unbolting it from the exhaust manifold and the exhaust pipe.
  4. Install the new catalytic converter, ensuring proper orientation.
  5. Bolt the converter in place and torque to manufacturer's specifications (typically around 30-40 ft-lbs).
  6. If cut, use appropriate exhaust clamps to secure the pipe connections.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Test drive the vehicle to ensure the check engine light does not reappear.