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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety glasses, gloves.
• Disconnect the negative battery terminal to prevent electrical short circuits.
• Allow the vehicle to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

1. Remove Oxygen Sensors:

   • Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
   • Using a socket wrench, carefully unscrew and remove both sensors.
   • Safety Warning: Ensure the exhaust system has cooled to prevent burns.

2. Install New Oxygen Sensors:

   • Apply anti-seize compound to the threads of the new oxygen sensors.
   • Install the upstream and downstream sensors, tightening them to the manufacturer's specifications (typically around 30 Nm).
   • Reconnect the electrical connectors for both sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Catalytic Converter:

   • Locate the catalytic converter in the exhaust system.
   • Using a socket set, unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
   • Carefully remove the catalytic converter from the vehicle.

2. Install New Catalytic Converter:

   • Position the new catalytic converter in place, aligning it with the exhaust manifold and pipe.
   • Bolt it securely, using a torque wrench to tighten to the manufacturer's specifications (usually around 40-50 Nm).
   • Ensure all gaskets are replaced and sealed properly.

4. Clear Codes and Test

1. Reconnect Battery:

   • Reconnect the negative battery terminal.

2. Clear Codes:

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

3. Test Drive:

   • Take the vehicle for a test drive to allow the ECU to complete readiness tests.