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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, penetrating oil
• Instructions:
  1. Locate the upstream (pre-cat) and downstream (post-cat) oxygen sensors.
  2. Apply penetrating oil to the sensor threads if they are corroded.
  3. Unplug the electrical connectors from both oxygen sensors.
  4. Using the O2 sensor socket, unscrew and remove the sensors.
  5. Install new oxygen sensors, tightening them to the manufacturer's specifications (typically around 30 Nm or 22 lb-ft).
  6. Reconnect the electrical connectors.

3. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger tool (if applicable)
• Instructions:
  1. Lift the vehicle and secure it on jack stands.
  2. Remove the exhaust pipes connected to the catalytic converter, loosening the clamps and nuts with a socket set.
  3. Remove any exhaust hangers using the exhaust hanger tool.
  4. Take out the old catalytic converter.
  5. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  6. Reattach exhaust pipes and secure with new clamps (if needed), tightening to specifications.
  7. Reinstall any exhaust hangers that were removed.

4. Clear the Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and any other related codes.