how to fix P0420 code on Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (usually near the exhaust manifold and after the catalytic converter).
  2. Remove the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust system.
  4. Install new oxygen sensors, torque to manufacturer specifications (typically around 30-35 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust sealant (if required)
• Sub-steps:
  1. If the catalytic converter is damaged or failed, remove the exhaust pipes connected to it (usually held by bolts or clamps).
  2. Carefully remove the catalytic converter, noting any gaskets or seals that may need replacement.
  3. Install the new catalytic converter, ensuring proper alignment and sealing. Torque the bolts to manufacturer specifications (typically around 25-30 ft-lbs).
  4. Reinstall any exhaust components removed during the process, ensuring a secure fit.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  3. Start the engine and allow it to reach operating temperature.
  4. Test drive the vehicle to ensure that the check engine light does not re-illuminate and monitor performance.