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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: Oxygen sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Remove the upstream (pre-catalytic) oxygen sensor by using the oxygen sensor socket.
  2. Install the new oxygen sensor and torque it to manufacturer specifications (typically around 30 ft-lbs).
  3. Repeat the process for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Jack and jack stands, socket set, exhaust pipe cutter (if necessary).
• Sub-steps:
  1. Raise the vehicle and secure it with jack stands.
  2. Remove the exhaust pipes connected to the catalytic converter using the socket set.
  3. If necessary, cut the exhaust pipe before and after the catalytic converter for easier removal.
  4. Install the new catalytic converter ensuring proper alignment with the exhaust system.
  5. Reattach exhaust pipes and torque fasteners to manufacturer specifications.

4. Reset the ECU

• 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. Start the engine and allow it to warm up while monitoring for any reoccurrence of the code.