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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
2. Using an O2 sensor socket, carefully remove the sensors.
3. Inspect the sensors for damage and replace if necessary.
4. Install new oxygen sensors, ensuring to torque them to the manufacturer’s specifications (typically around 30 ft-lbs).
5. Reconnect the battery.

3. Inspect and Replace the Catalytic Converter

1. If oxygen sensors are functioning correctly, proceed to inspect the catalytic converter.
2. Remove the bolts securing the catalytic converter to the exhaust system using a socket set.
3. Carefully lower the catalytic converter from its mounting location.
4. Inspect the catalytic converter for any signs of physical damage or excessive carbon buildup.
5. If necessary, replace the catalytic converter with a new unit, ensuring it meets OEM specifications.
6. Reinstall the catalytic converter, tightening bolts to the manufacturer’s torque specifications (typically around 40 ft-lbs).

4. Clear Codes and Test Drive

1. Use the OBD-II scanner to clear any stored trouble codes from the vehicle's memory.
2. Start the engine and allow it to reach operating temperature.
3. Test drive the vehicle under various conditions to ensure the check engine light does not reappear.