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

Solution

1. Preparation

• Disconnect the battery to ensure safety while working on the electrical system.
• Gather all necessary tools and parts.
• Raise the vehicle securely on jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor by:
  1. Locating the sensor on the exhaust manifold or pipe.
  2. Using the O2 sensor socket to unscrew the sensor.
  3. Installing the new sensor and tightening it to the manufacturer's specification (usually around 30 lb-ft).
• Repeat the process for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket
• Remove the old catalytic converter by:
  1. Loosening the bolts securing it to the exhaust manifold and exhaust pipe.
  2. Carefully removing the catalytic converter from its mounting points.
• Install the new catalytic converter by:
  1. Placing the new converter in position.
  2. Securing it with bolts and gaskets, tightening to the specified torque (typically around 30-40 lb-ft).

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.