how to fix P0420 exhaust issue in Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the Downstream Oxygen Sensor

   • Locate the downstream oxygen sensor (usually located after the catalytic converter).
   • Use an O2 sensor socket to unscrew the sensor from the exhaust manifold.

2. Install New Downstream Oxygen Sensor

   • Apply anti-seize compound to the threads of the new sensor.
   • Screw in the new sensor and tighten it to the manufacturer's specifications (typically around 30 lb-ft).
   • Reconnect the electrical connector.

3. Inspect and Replace the Catalytic Converter

1. Remove the Old Catalytic Converter

   • Unbolt the exhaust pipe bolts connecting to the catalytic converter using a socket set.
   • If applicable, remove any heat shields or brackets holding the converter in place.
   • Carefully remove the catalytic converter from its mounting position.

2. Install New Catalytic Converter

   • Position the new catalytic converter in place and secure it with bolts to the exhaust system.
   • Ensure all connections are tight and properly aligned.
   • Reinstall any heat shields or brackets if previously removed.

4. Final Checks

• Reconnect the battery.
• Clear the P0420 code using the OBD-II scanner.
• Start the engine and check for exhaust leaks around the new components.