how to fix P0420 code in Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the vehicle battery (negative terminal).
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil
• Steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Apply penetrating oil to the threads of the sensors and allow it to sit for a few minutes.
  3. Carefully remove the upstream and downstream oxygen sensors using an O2 sensor socket.
  4. Install the new oxygen sensors using the torque wrench to the manufacturer’s specifications (usually around 30 ft-lbs).
  5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
  3. Use an exhaust hanger removal tool to detach any hangers securing the catalytic converter.
  4. Remove the old catalytic converter from the vehicle.
  5. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  6. Torque the bolts to the manufacturer’s specifications.
  7. Reattach any exhaust hangers that were removed.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Steps:
  1. Reconnect the vehicle battery (positive terminal first, then negative).
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and let it reach operating temperature.
  4. Take the vehicle for a test drive to ensure the check engine light does not reappear.