how to fix P0420 code in Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal.
• Raise the vehicle safely on jack stands or use a lift.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  • Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors on the exhaust system.
  • Unplug the electrical connectors from both sensors.
  • Remove the sensors using an O2 sensor socket.
  • Install new oxygen sensors and torque to manufacturer specifications (typically around 30 ft-lbs).
  • Reconnect the electrical connectors.

3. Check and Replace Catalytic Converter

• Sub-steps:
  • Inspect the catalytic converter for signs of blockage or damage.
  • Remove the exhaust clamps and bolts securing the catalytic converter to the exhaust system.
  • Carefully detach the catalytic converter.
  • Install the new catalytic converter, ensuring proper alignment and sealing.
  • Torque bolts to manufacturer specifications (typically around 40-50 ft-lbs).
  • Reinstall exhaust clamps.

4. Clear Codes and Test

• Use an OBD-II scanner to clear the P0420 code from the ECU.
• Reconnect the negative battery terminal.
• Start the engine and let it idle for a few minutes.