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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shorts during repair.
• Raise the vehicle and secure it on jack stands if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
• Remove the upstream O2 sensor by:
  1. Disconnecting the electrical connector.
  2. Using the O2 sensor socket to unscrew the sensor.
  3. Installing the new sensor by reversing the steps, ensuring to torque to manufacturer specifications (typically 30-40 ft-lbs).
• Repeat for the downstream O2 sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Wrench set, cutting tool (if necessary), exhaust gasket, torque wrench.
• Inspect the catalytic converter for physical damage or blockage.
• If replacement is needed:
  1. Disconnect the exhaust pipes from the catalytic converter.
  2. Remove any heat shields covering the catalytic converter.
  3. Unbolt the catalytic converter from its mounting brackets.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reattach any exhaust pipes and torque to manufacturer specifications.
  6. Replace exhaust gaskets as necessary to prevent leaks.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and conduct a test drive to ensure the issue is resolved.