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

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream sensor and inspect it for damage.
  3. If necessary, replace the upstream sensor with a new one. Torque to manufacturer specifications (usually around 30 lb-ft).
  4. Repeat the process for the downstream sensor if it shows signs of malfunction.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust gasket.
• Sub-steps:
  1. Raise the vehicle securely on jack stands.
  2. Locate the catalytic converter and inspect it for any signs of physical damage or blockage.
  3. Remove the exhaust bolts securing the catalytic converter to the exhaust system.
  4. Carefully detach the catalytic converter from the exhaust system; it may require gentle prying.
  5. Install the new catalytic converter, ensuring to use a new gasket and torque the bolts to the manufacturer's specifications.

4. Reset the ECU

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's ECU.

5. Final Inspection

• Sub-steps:
  1. Start the engine and check for exhaust leaks around the newly installed components.
  2. Monitor the vehicle for any abnormal sounds or performance issues.