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

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, torque wrench, new catalytic converter (if needed), oxygen sensors (if needed).
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, socket wrench
• Sub-steps:
  1. Disconnect the battery to prevent any electrical shorts.
  2. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  3. Use the O2 sensor socket to unscrew the sensors from the exhaust system.
  4. Install new oxygen sensors in reverse order and torque to manufacturer specifications (usually around 30 ft-lbs).
  5. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hangers removal tool
• Sub-steps:
  1. Raise the vehicle using jack stands for safety.
  2. Disconnect any heat shields and exhaust hangers attached to the catalytic converter.
  3. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
  4. Compare the old catalytic converter with the new one for correct fitment.
  5. Install the new catalytic converter, tightening bolts to the manufacturer’s torque specifications.
  6. Reattach heat shields and exhaust hangers.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code.
  2. Start the engine and allow it to reach operating temperature.
  3. Take the vehicle for a test drive to ensure proper operation.