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

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Using the O2 sensor socket, carefully remove the upstream sensor.
  3. Install the new oxygen sensor in the upstream position and torque it to the manufacturer's specification (usually around 30-40 lb-ft).
  4. Repeat for the downstream sensor if necessary.

3. Check and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)
• Sub-steps:
  1. Disconnect the exhaust pipes from the catalytic converter by removing the bolts or clamps.
  2. If the catalytic converter is damaged or clogged, remove it from the vehicle.
  3. Install the new catalytic converter, ensuring that the inlet and outlet pipes are properly aligned.
  4. Torque all bolts to the specified values (consult the repair manual for exact torque specifications).

4. Clear Codes and Test

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code and any other related codes.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to ensure the check engine light does not reappear.