my Honda Pilot YF3 (2016-2022) has a check engine light and code P0420, what should I do?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery negative terminal to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Remove the upstream oxygen sensor:
  • Use an oxygen sensor socket to carefully unscrew the sensor from the exhaust manifold.
• Replace with a new oxygen sensor:
  • Install the new sensor and torque it to the manufacturer's specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

• Remove the exhaust system components:
  • Loosen and remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
  • Use penetrating oil if the bolts are rusted.
• Remove the catalytic converter:
  • Carefully detach it from the exhaust system.
• Install the new catalytic converter:
  • Ensure proper alignment and secure it with new gaskets and bolts, torquing to manufacturer's specifications (usually around 25-30 ft-lbs).

4. Reconnect Battery

• Reconnect the battery negative terminal securely.

5. Clear Codes and Test

• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature, then perform a test drive to ensure the issue is resolved.