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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Oxygen Sensors

• Tools Required:

  • O2 sensor socket or wrench
  • Torque wrench

• 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 the O2 sensor socket to remove the sensors.
  4. Install the new oxygen sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Tools Required:

  • Jack and jack stands
  • Socket set
  • Exhaust gasket
  • Torque wrench

• Sub-steps:

  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Disconnect the exhaust pipe from the catalytic converter by removing the bolts.
  3. Remove any heat shields if present.
  4. Detach the catalytic converter from the exhaust manifold or pipe.
  5. Install the new catalytic converter with an exhaust gasket, ensuring proper alignment.
  6. Reattach the exhaust pipe and tighten all bolts to the specified torque (check the service manual for exact values).

4. Final Check

• Reconnect the negative battery terminal.
• Start the engine and let it idle for a few minutes to check for leaks and proper operation.