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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Use an oxygen sensor socket to unscrew the sensor from the exhaust manifold.
   • Check the sensor's condition; if it appears damaged or corroded, replace it.

2. Remove the downstream oxygen sensor:

   • Follow the same process to remove the sensor located after the catalytic converter.
   • Inspect for damage and replace if necessary.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the exhaust system components:

   • Loosen and remove bolts or clamps holding the exhaust pipe to the catalytic converter using a socket set.
   • Carefully detach the exhaust pipe from the catalytic converter.

2. Remove the catalytic converter:

   • Unbolt the catalytic converter from the mounting brackets.
   • Inspect the converter for damage or blockage; if defective, install a new catalytic converter.

3. Install new catalytic converter:

   • Position the new catalytic converter in place and secure it with bolts, ensuring proper alignment.
   • Torque bolts to the manufacturer's specifications (typically around 30-40 ft-lbs).

4. Reinstall Exhaust Components

• Reattach the exhaust pipe to the catalytic converter and secure it with bolts/clamps.
• Ensure all connections are tight and leak-free.

5. Clear the Codes and Test Drive

1. Reconnect the battery:

   • Reattach the negative battery terminal.

2. Clear the OBD-II codes:

   • Use the OBD-II scanner to clear the P0420 code.

3. Test drive the vehicle:

   • Drive the vehicle for a short distance to allow the ECU to monitor sensor readings.