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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, temperature gun, safety glasses, gloves
• Ensure the vehicle is parked on a level surface, and the engine is cool before starting work.

2. Address Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system for any cracks or holes.
  2. Use a jack to lift the vehicle if necessary, and check for leaks around the catalytic converter and joints.
  3. Repair any leaks found using exhaust sealant or replace damaged sections of the exhaust system.

3. Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Remove the sensors using an oxygen sensor socket or wrench.
  4. Install new sensors by reversing the removal steps, ensuring they are securely tightened to the manufacturer’s specifications (usually around 30 lb-ft).

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields covering the catalytic converter if applicable.
  2. Disconnect the exhaust pipe from the catalytic converter by removing the bolts or clamps.
  3. Remove the catalytic converter from its mounting points.
  4. Install the new catalytic converter, ensuring proper orientation and alignment.
  5. Reattach the exhaust pipe and torque bolts to manufacturer specifications.

5. Reset Check Engine Light

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the computer.
  2. Start the engine and allow it to reach operating temperature.
  3. Monitor for any reoccurrence of the P0420 code.