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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety glasses, gloves.
• Safety Warnings: Disconnect the battery before working on electrical systems.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors: Find the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the Sensors: Unplug the electrical connectors from both sensors.
3. Remove the Sensors: Use a socket wrench to remove the oxygen sensors from their respective locations.
4. Install New Sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Thread in the new sensors and tighten to manufacturer specifications (generally around 30 lb-ft).
5. Reconnect the Sensors: Plug the electrical connectors back into the sensors.

3. Inspect and Replace Catalytic Converter

1. Remove Exhaust Components: Use a socket wrench to unbolt any heat shields or exhaust components that may be in the way of the catalytic converter.
2. Unbolt the Catalytic Converter: Remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
3. Install New Catalytic Converter:
   • Position the new catalytic converter in place.
   • Secure it with the bolts, tightening them to the specified torque (usually around 30 lb-ft).
4. Reassemble Exhaust Components: Reattach any heat shields or exhaust components removed earlier.

4. Clear Codes and Test Drive

1. Reconnect the Battery: Ensure the battery is reconnected after all repairs.
2. Clear the Error Codes: Use the OBD-II scanner to clear the P0420 code.
3. Test Drive the Vehicle: Drive the car for at least 20 minutes to allow the ECU to re-evaluate the catalytic converter efficiency.