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 electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors. The upstream sensor is before the catalytic converter, and the downstream sensor is after it.
  2. Disconnect the electrical connectors from both oxygen sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new oxygen sensors. Torque the sensors to the manufacturer's specification (typically 30 Nm or 22 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Sub-steps:
  1. If the catalytic converter is found to be damaged or clogged, raise the vehicle using jack stands.
  2. Remove the bolts securing the catalytic converter to the exhaust pipes using a socket set.
  3. If the converter is welded in place, carefully cut it out using an exhaust pipe cutter.
  4. Install the new catalytic converter by aligning it with the exhaust system. Secure it with bolts, torquing them according to specifications.
  5. Reconnect any oxygen sensors removed during the process.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code and monitor for any reoccurrence.