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

Solution

1. Preparation

• Gather tools and materials needed for the repair.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, exhaust pipe cutter, safety goggles, gloves.
• Safety Warnings: Disconnect the battery before starting work on electrical components. Allow the engine to cool before working on exhaust components.

2. Replace Oxygen Sensors (if faulty)

• Remove the upstream and downstream oxygen sensors using a socket wrench.
• Inspect the wiring harness for any damage or corrosion. Repair as necessary.
• Install new oxygen sensors, tightening them to the manufacturer's specifications (typically around 30 Nm).
• Reconnect the electrical connectors for the oxygen sensors.

3. Inspect and Replace Catalytic Converter (if needed)

• Remove Exhaust Components:

  • Use an exhaust pipe cutter to cut through any rusted or damaged sections of the exhaust near the catalytic converter.
  • Remove mounting bolts and brackets securing the catalytic converter to the exhaust system.

• Install New Catalytic Converter:

  • Position the new catalytic converter in place and secure it with mounting hardware.
  • Torque all fasteners to the manufacturer's specifications (consult repair manual for exact torque values).

4. Clear Codes and Test

• Reconnect the battery and use the OBD-II scanner to clear any stored codes.
• Start the engine and allow it to reach operating temperature, then conduct a test drive to ensure the check engine light does not reappear.