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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical short circuits.
• Raise the vehicle securely using jack stands if necessary.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install new oxygen sensors, tightening them to the manufacturer's specified torque (typically around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if applicable).
• Sub-steps:
  1. Inspect the catalytic converter for signs of damage or clogging.
  2. If replacement is needed, disconnect the exhaust pipes connected to the catalytic converter.
  3. Use an exhaust pipe cutter to remove the old catalytic converter if required.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Secure it with the appropriate bolts, tightening them to the manufacturer's specified torque.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use an OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.