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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, dielectric grease.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use the O2 sensor socket to remove the upstream oxygen sensor.
  3. Install the new upstream oxygen sensor and torque to manufacturer specifications (typically around 30 ft-lbs).
  4. Repeat steps 2 and 3 for the downstream oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Sub-steps:
  1. If the catalytic converter is damaged or clogged, remove it from the exhaust system.
  2. Use the socket set to remove the bolts securing the catalytic converter to the exhaust manifold and the rear exhaust pipe.
  3. Install the new catalytic converter, ensuring proper alignment with exhaust hangers.
  4. Torque the bolts to manufacturer specifications (typically around 25 ft-lbs for exhaust components).

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  3. Test drive the vehicle under various conditions to confirm the repair and monitor for any reoccurrence of the code.