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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and set the parking brake.
• Disconnect the battery to prevent any electrical issues during repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and extension.
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the upstream O2 sensor on the exhaust manifold.
  2. Use the O2 sensor socket to unscrew and remove the sensor.
• Install the new upstream oxygen sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Install the new O2 sensor and tighten it to manufacturer specifications (typically 30-40 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, jack, jack stands.
• Raise the vehicle using a jack and secure it with jack stands.
• Remove the catalytic converter:
  1. Disconnect any bolts or clamps securing the catalytic converter to the exhaust system.
  2. Carefully remove the catalytic converter from the exhaust system.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Reattach bolts or clamps and tighten to manufacturer specifications.

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.