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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the upstream oxygen sensor (before the catalytic converter).
  • Ensure the engine is cool to prevent burns.
  • Use a wrench to carefully unscrew the sensor.
• Test the sensor’s voltage output with a multimeter.
  • Expected range: 0.1 to 0.9 volts.
• If faulty, replace the oxygen sensor with a new one.

3. Inspect and Clean Catalytic Converter

• Tools Required: Socket set, torque wrench
• If the catalytic converter is accessible, remove it from the exhaust system.
  • Use a socket wrench to loosen the bolts and detach it.
• Inspect for any signs of blockage or physical damage.
• If heavily clogged, consider cleaning it with a specialized catalytic converter cleaner or replace it.
  • If cleaning, follow the product instructions carefully.
• Reinstall the catalytic converter, ensuring all bolts are tightened to the manufacturer’s specifications (usually around 30-35 ft-lbs).

4. Reconnect Components

• Reinstall the upstream oxygen sensor if it was removed.
• Reconnect the negative battery terminal.
• Clear the P0420 code using the OBD-II scanner.