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

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the vehicle battery to ensure safety during repairs.
• Raise the vehicle securely on jack stands or ramps.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (before the catalytic converter) using the O2 sensor socket.
  • Sub-step: Carefully disconnect the electrical connector.
• Inspect the sensor for damage; replace if necessary.
• Repeat the process for the downstream oxygen sensor (after the catalytic converter).
• Torque the new sensors to the manufacturer's specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Remove any heat shields or brackets obstructing access to the catalytic converter.
• Unbolt the catalytic converter from the exhaust system, ensuring to support it to avoid damage.
  • Sub-step: Cut the exhaust pipes if they are rusted or fused.
• Install the new catalytic converter, ensuring proper alignment and fit.
• Torque all bolts to the manufacturer's specifications (typically around 40 lb-ft for catalytic converter bolts).
• Reattach any heat shields or brackets.

4. Clear Codes and Test

• Reconnect the vehicle battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.
• Test drive the vehicle under various conditions (idle, acceleration, highway) to ensure the code does not return.