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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent any electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using a wrench, carefully disconnect the electrical connectors from both sensors.
3. Remove the sensors using an oxygen sensor socket.
4. Install new oxygen sensors, ensuring they are properly threaded and tightened to the manufacturer’s specifications (usually around 30 ft-lbs).
5. Reconnect the electrical connectors to the sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove any heat shields or brackets securing the catalytic converter.
2. Disconnect the exhaust pipe from the catalytic converter by loosening the clamps or bolts.
3. Remove the catalytic converter from the vehicle.
4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
5. Reattach any heat shields or brackets removed earlier.

4. Clear Codes and Test

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear any trouble codes from the PCM.
3. Start the engine and let it idle for a few minutes.
4. Take the vehicle for a test drive to ensure the P0420 code does not return.