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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical issues while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors (usually found in the exhaust manifold and after the catalytic converter).
2. Using a socket wrench, carefully remove the oxygen sensors.
3. Inspect the sensors for any signs of damage or carbon buildup. If they are defective, replace them with new sensors.
4. Apply anti-seize compound to the threads of the new sensors before installation.
5. Reinstall the oxygen sensors and torque them to manufacturer specifications (typically around 30 lb-ft).

3. Examine and Replace the Catalytic Converter (if necessary)

1. Inspect the catalytic converter visually for any signs of damage or blockage.
2. If replacement is needed, disconnect any clamps or bolts securing it to the exhaust system.
3. Carefully remove the old catalytic converter from its mountings.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
5. Torque all bolts to the specifications provided in the vehicle service manual.

4. Reconnect Battery and Clear Codes

1. Reconnect the negative terminal of the battery.
2. Use the OBD-II scanner to clear any stored trouble codes from the vehicle’s computer.