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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using a socket wrench, carefully unscrew and remove the upstream oxygen sensor.
3. Inspect the sensor for signs of damage or contamination.
4. Install a new upstream oxygen sensor (ensure it matches OEM specifications) and torque it to manufacturer specifications (typically around 30 ft-lbs).
5. Repeat the process for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

1. If the catalytic converter is found to be damaged or blocked, proceed with removal.
2. Remove the exhaust hangers using a hangar removal tool to detach the exhaust system from the catalytic converter.
3. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using a socket set.
4. Compare the old catalytic converter with the new one to ensure proper fit.
5. Install the new catalytic converter and tighten the bolts to the specified torque (usually around 30 ft-lbs).
6. Reattach the exhaust hangers securely.

4. Reset the Check Engine Light

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Start the engine and allow it to reach operating temperature.