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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.
• Allow the vehicle to cool down if the engine has been running.

Tools Required:

• OBD-II scanner
• Socket set
• Multimeter
• Torque wrench
• Jack and jack stands

2. Inspect and Clean Components

1. Inspect Oxygen Sensors:

   • Identify the upstream and downstream oxygen sensors.
   • Remove the upstream oxygen sensor using a socket.
   • Inspect for carbon buildup; clean if necessary using a suitable cleaner.
   • Reinstall the sensor and torque to manufacturer's specification (usually around 30 lb-ft).

2. Inspect Catalytic Converter:

   • Visually inspect for any signs of damage or blockage.
   • If damaged, remove the catalytic converter using a socket set.
   • Check for excessive soot or debris inside; clean if applicable or replace if necessary.

3. Replace Catalytic Converter (if needed)

1. Remove Old Catalytic Converter:

   • Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
   • Carefully remove the converter from the vehicle.

2. Install New Catalytic Converter:

   • Position the new catalytic converter in place.
   • Secure it with bolts, using a torque wrench to tighten to the specified torque (usually around 40 lb-ft).
   • Ensure all gaskets are replaced to prevent leaks.

4. Reset the OBD-II System

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the engine control unit (ECU).
• Start the engine and allow it to run for a few minutes to ensure proper operation.