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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use an O2 sensor socket to remove the upstream sensor first.
  3. Install the new upstream oxygen sensor and torque it to the manufacturer’s specifications (usually around 30-40 ft-lbs).
  4. Repeat the process for the downstream oxygen sensor.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Raise the vehicle securely on jack stands.
  2. Remove any heat shields covering the catalytic converter (if applicable).
  3. Unbolt and remove the catalytic converter from the exhaust system using a socket set.
  4. Inspect the exhaust pipes for damage and replace if necessary.
  5. Install the new catalytic converter, ensuring proper alignment and sealing.
  6. Torque the bolts to the manufacturer’s specifications (typically around 30-50 ft-lbs).

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use the OBD-II scanner to clear the P0420 code from the ECU.
  3. Start the engine and allow it to reach operating temperature.