how to fix P0420 code on Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, wrench set
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new oxygen sensors and torque them to the manufacturer's specifications (typically around 30-40 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, exhaust pipe cutter, or saw, jack stands
• Sub-steps:
  1. Lift the vehicle safely using jack stands.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Cut or unbolt the exhaust pipes connected to the catalytic converter.
  4. Remove the old catalytic converter and replace it with a new one, ensuring proper alignment.
  5. Reattach the exhaust pipes and any heat shields, torquing to specifications.

4. Clear the Codes and Test Drive

• 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 memory.
  3. Start the engine and let it idle for a few minutes.
  4. Take the vehicle for a test drive to monitor for any reoccurrence of the P0420 code.