how to fix P0420 code in Honda Pilot Third Generation (2016-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 negative terminal to avoid electrical shorts.

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  1. Use a flashlight to visually inspect the exhaust pipes and connections for signs of leaks.
  2. If any leaks are found, repair or replace the affected sections of the exhaust system.
• Tools required: Socket set, exhaust sealant or replacement pipe.

3. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors near the catalytic converter.
  2. Disconnect the wiring harness from the sensors.
  3. Use an oxygen sensor socket to remove the sensors from the exhaust system.
  4. Install the new oxygen sensors by screwing them into place and reconnecting the wiring harness.
• Tools required: Oxygen sensor socket, wrench, torque wrench (typically 30-40 ft-lbs for sensor installation).

4. Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
  2. Remove the old catalytic converter from the vehicle.
  3. Install the new catalytic converter by reversing the removal process, ensuring all gaskets and seals are in good condition.
• Tools required: Socket set, torque wrench (specific torque values depend on the manufacturer).

5. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery negative terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Tools required: OBD-II scanner.