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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface with the engine off.
• Disconnect the battery to avoid electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil
• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Apply penetrating oil to the sensor threads if they're stuck.
• Disconnect the electrical connectors from both oxygen sensors.
• Use an O2 sensor socket to remove the sensors and replace them with new ones, torquing them to the manufacturer's specifications (typically around 30 ft-lbs).
• Reconnect the electrical connectors.

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

• Tools Required: Socket set, torque wrench, exhaust sealant
• If testing indicates a faulty catalytic converter, raise the vehicle on jack stands.
• Disconnect the exhaust pipes from the catalytic converter using a socket set.
• Remove any mounting hardware securing the catalytic converter.
• Install the new catalytic converter in the reverse order of removal, ensuring all bolts are torqued to specifications (usually around 25-30 ft-lbs) and use exhaust sealant if necessary to prevent leaks.
• Reconnect the exhaust system.

4. Clear Codes and Test Drive

• Reconnect the battery and start the engine.
• Use the OBD-II scanner to clear the P0420 code.
• Perform a test drive to allow the vehicle's computer to run diagnostics on the catalytic converter and oxygen sensors.