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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down before starting work on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:
   • Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove the Oxygen Sensors:
   • Use an oxygen sensor socket to unscrew the sensors from the exhaust manifold and catalytic converter.
   • Disconnect the electrical connectors from each sensor.
3. Install New Oxygen Sensors:
   • Apply anti-seize compound on the threads of the new oxygen sensors.
   • Install the new sensors into their respective positions and tighten to manufacturer specifications (usually around 30 ft-lbs).
   • Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the Catalytic Converter:
   • Unbolt the catalytic converter from the exhaust system using a socket set (torque specifications may vary).
   • Ensure all gaskets are removed as well.
2. Install New Catalytic Converter:
   • Position the new catalytic converter and secure it with new gaskets.
   • Tighten bolts to specified torque values (typically around 30-40 ft-lbs).
3. Check for Exhaust Leaks:
   • Start the engine and inspect for any exhaust leaks around the newly installed components.

4. Clear Codes and Test Drive

1. Reconnect Battery:
   • Reconnect the negative battery terminal.
2. Clear the P0420 Code:
   • Use the OBD-II scanner to clear the fault codes from the vehicle's computer.
3. Test Drive:
   • Drive the vehicle under various conditions to ensure the issue is resolved and the check engine light does not reappear.