how to fix P0420 code in Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool completely before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench

• Remove the upstream (pre-catalytic) oxygen sensor:

  1. Locate the upstream O2 sensor in the exhaust manifold area.
  2. Use the O2 sensor socket to unscrew and remove the sensor.
  3. Install the new O2 sensor, tightening it to the manufacturer's specifications (typically around 30 lb-ft).

• Remove the downstream (post-catalytic) oxygen sensor:

  1. Locate the downstream O2 sensor near the catalytic converter.
  2. Repeat the removal and installation process as with the upstream sensor.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, wrench set, exhaust pipe cutter (if needed), gasket scraper

• Remove the catalytic converter:

  1. Locate the catalytic converter along the exhaust system.
  2. Disconnect the exhaust pipes by removing the bolts or clamps securing it.
  3. If necessary, cut the exhaust pipe using the exhaust pipe cutter.

• Install the new catalytic converter:

  1. Clean the mating surfaces of the exhaust pipes to ensure a proper seal.
  2. Position the new catalytic converter in place and secure it with new gaskets and hardware.
  3. Torque all bolts to the manufacturer's specifications.

4. Reconnect Battery and Clear Codes

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's memory.