how to fix P0420 code on my Honda Pilot YF3 (2016-2022)

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.

2. Inspect Oxygen Sensors

• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Use a wrench to carefully remove the sensors.
• Inspect the wiring and connectors for damage or corrosion.
• If faulty, replace the oxygen sensors with new ones.

3. Check and Replace the Catalytic Converter

• Inspect the catalytic converter for any physical damage, such as dents or excessive rust.
• If damaged, use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
  • Tools required: Socket set, penetrating oil (if bolts are rusted).
• Replace with a new catalytic converter, ensuring all gaskets are in place.

4. Reconnect and Test

• Reconnect the oxygen sensors with new gaskets if necessary.
• Reconnect the battery.
• Clear the P0420 code using the OBD-II scanner.
• Start the engine and let it idle for a few minutes.

5. Test Drive

• Take the vehicle for a test drive to allow the engine control unit (ECU) to monitor the catalytic converter's performance.
• Check for any reappearance of the P0420 code.