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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety goggles, gloves.
• Park the vehicle on a level surface and ensure the engine is cool. Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the oxygen sensors from the exhaust pipe.
  4. Install new oxygen sensors, ensuring they are properly torqued to manufacturer specifications (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. If the oxygen sensors are functioning properly and the code persists, locate the catalytic converter.
  2. Use a socket set to remove any bolts securing the catalytic converter to the exhaust system.
  3. Inspect the catalytic converter for physical damage or excessive soot buildup.
  4. If damaged, replace with a new catalytic converter, ensuring the correct fit and compatibility with the vehicle.
  5. Torque the mounting bolts to the specified value (usually around 40-50 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.