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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and torque wrench.
• 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 sensors from their respective locations.
  4. Install new oxygen sensors by threading them in carefully and tightening them to the manufacturer’s specified torque (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, and cutting tool (if needed).
• Steps:
  1. Inspect the catalytic converter for any physical damage or signs of clogging.
  2. If replacement is needed, unbolt the exhaust flanges before and after the catalytic converter.
  3. Remove the catalytic converter from the exhaust system. If necessary, use a cutting tool to remove it.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Bolt the flanges back together and tighten to the specified torque (usually around 30 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the P0420 code and reset the check engine light.