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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use an oxygen sensor socket to remove the upstream sensor.
     • Tools Required: Oxygen sensor socket, ratchet.
  3. Inspect the sensor for damage; replace if necessary.
  4. Repeat the removal process for the downstream sensor.
  5. Install new oxygen sensors and torque to the manufacturer’s specification (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Inspect for dents, rust, or other signs of damage.
  3. If replacement is necessary, remove the bolts securing it to the exhaust system using a socket set.
     • Tools Required: Socket set, penetrating oil (if bolts are rusted).
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Torque bolts to manufacturer specifications (typically around 30 ft-lbs).

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and allow it to reach operating temperature.
  4. Drive the vehicle under various conditions (city and highway) for at least 20 minutes to allow the vehicle’s computer to re-evaluate the system.