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

Solution

1. Preparation

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

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system from the manifold to the tailpipe for cracks or holes.
  2. If a leak is found, use exhaust repair tape or replace damaged sections of the exhaust pipe.
• Tools Required: Socket set, exhaust repair tape or replacement pipe.

3. Replace Faulty Oxygen Sensors (if needed)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the electrical connectors from the sensors.
  3. Use an oxygen sensor socket to remove the sensors from their positions.
  4. Install new sensors, ensuring they are tightened to manufacturer's specifications (usually around 30-40 lb-ft).
  5. Reconnect the electrical connectors.
• Tools Required: Oxygen sensor socket, torque wrench.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust system components that obstruct access to the catalytic converter (e.g., heat shields).
  2. Disconnect the catalytic converter from the exhaust manifold and the exhaust pipe.
  3. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  4. Tighten all connections to manufacturer specifications.
• Tools Required: Socket set, torque wrench.

5. Reconnect Battery

• Reconnect the negative battery terminal after repairs are complete.